Add pokemon evolution support across the full stack

- Evolution model with trigger, level, item, and condition fields
- Encounter.current_pokemon_id tracks evolved species separately
- Alembic migration for evolutions table and current_pokemon_id column
- Seed pipeline loads evolution data with manual overrides
- GET /pokemon/{id}/evolutions and PATCH /encounters/{id} endpoints
- Evolve button in StatusChangeModal with evolution method details
- PokemonCard shows evolved species with "Originally" label

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/app/alembic/versions/b2c3d4e5f6a7_add_evolutions_and_current_pokemon.py

@@ -0,0 +1,42 @@
+"""add evolutions table and current_pokemon_id to encounters
+
+Revision ID: b2c3d4e5f6a7
+Revises: a1b2c3d4e5f6
+Create Date: 2026-02-05 18:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'b2c3d4e5f6a7'
+down_revision: Union[str, Sequence[str], None] = 'a1b2c3d4e5f6'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        'evolutions',
+        sa.Column('id', sa.Integer(), primary_key=True),
+        sa.Column('from_pokemon_id', sa.Integer(), sa.ForeignKey('pokemon.id'), nullable=False, index=True),
+        sa.Column('to_pokemon_id', sa.Integer(), sa.ForeignKey('pokemon.id'), nullable=False, index=True),
+        sa.Column('trigger', sa.String(30), nullable=False),
+        sa.Column('min_level', sa.SmallInteger(), nullable=True),
+        sa.Column('item', sa.String(50), nullable=True),
+        sa.Column('held_item', sa.String(50), nullable=True),
+        sa.Column('condition', sa.String(200), nullable=True),
+    )
+
+    op.add_column(
+        'encounters',
+        sa.Column('current_pokemon_id', sa.Integer(), sa.ForeignKey('pokemon.id'), nullable=True, index=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column('encounters', 'current_pokemon_id')
+    op.drop_table('evolutions')

backend/src/app/api/encounters.py

@@ -1,12 +1,19 @@
 from fastapi import APIRouter, Depends, HTTPException, Response
+from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import joinedload
 
 from app.core.database import get_session
 from app.models.encounter import Encounter
 from app.models.nuzlocke_run import NuzlockeRun
 from app.models.pokemon import Pokemon
 from app.models.route import Route
-from app.schemas.encounter import EncounterCreate, EncounterResponse, EncounterUpdate
+from app.schemas.encounter import (
+    EncounterCreate,
+    EncounterDetailResponse,
+    EncounterResponse,
+    EncounterUpdate,
+)
 
 router = APIRouter()
 
@@ -50,7 +57,7 @@ async def create_encounter(
     return encounter
 
 
-@router.patch("/encounters/{encounter_id}", response_model=EncounterResponse)
+@router.patch("/encounters/{encounter_id}", response_model=EncounterDetailResponse)
 async def update_encounter(
     encounter_id: int,
     data: EncounterUpdate,
@@ -65,8 +72,18 @@ async def update_encounter(
         setattr(encounter, field, value)
 
     await session.commit()
-    await session.refresh(encounter)
+
-    return encounter
+    # Reload with relationships for detail response
+    result = await session.execute(
+        select(Encounter)
+        .where(Encounter.id == encounter_id)
+        .options(
+            joinedload(Encounter.pokemon),
+            joinedload(Encounter.current_pokemon),
+            joinedload(Encounter.route),
+        )
+    )
+    return result.scalar_one()
 
 
 @router.delete("/encounters/{encounter_id}", status_code=204)

backend/src/app/api/pokemon.py

@@ -4,12 +4,14 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import joinedload, selectinload
 
 from app.core.database import get_session
+from app.models.evolution import Evolution
 from app.models.pokemon import Pokemon
 from app.models.route import Route
 from app.models.route_encounter import RouteEncounter
 from app.schemas.pokemon import (
     BulkImportItem,
     BulkImportResult,
+    EvolutionResponse,
     PokemonCreate,
     PokemonResponse,
     PokemonUpdate,
@@ -101,6 +103,22 @@ async def get_pokemon(
     return pokemon
 
 
+@router.get("/pokemon/{pokemon_id}/evolutions", response_model=list[EvolutionResponse])
+async def get_pokemon_evolutions(
+    pokemon_id: int, session: AsyncSession = Depends(get_session)
+):
+    pokemon = await session.get(Pokemon, pokemon_id)
+    if pokemon is None:
+        raise HTTPException(status_code=404, detail="Pokemon not found")
+
+    result = await session.execute(
+        select(Evolution)
+        .where(Evolution.from_pokemon_id == pokemon_id)
+        .options(joinedload(Evolution.to_pokemon))
+    )
+    return result.scalars().unique().all()
+
+
 @router.put("/pokemon/{pokemon_id}", response_model=PokemonResponse)
 async def update_pokemon(
     pokemon_id: int,

backend/src/app/api/runs.py

@@ -51,6 +51,8 @@ async def get_run(run_id: int, session: AsyncSession = Depends(get_session)):
             selectinload(NuzlockeRun.encounters)
             .joinedload(Encounter.pokemon),
             selectinload(NuzlockeRun.encounters)
+            .joinedload(Encounter.current_pokemon),
+            selectinload(NuzlockeRun.encounters)
             .joinedload(Encounter.route),
         )
     )

backend/src/app/models/__init__.py

@@ -1,4 +1,5 @@
 from app.models.encounter import Encounter
+from app.models.evolution import Evolution
 from app.models.game import Game
 from app.models.nuzlocke_run import NuzlockeRun
 from app.models.pokemon import Pokemon
@@ -7,6 +8,7 @@ from app.models.route_encounter import RouteEncounter
 
 __all__ = [
     "Encounter",
+    "Evolution",
     "Game",
     "NuzlockeRun",
     "Pokemon",

backend/src/app/models/encounter.py

@@ -18,13 +18,21 @@ class Encounter(Base):
     catch_level: Mapped[int | None] = mapped_column(SmallInteger)
     faint_level: Mapped[int | None] = mapped_column(SmallInteger)
     death_cause: Mapped[str | None] = mapped_column(String(100))
+    current_pokemon_id: Mapped[int | None] = mapped_column(
+        ForeignKey("pokemon.id"), index=True
+    )
     caught_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), server_default=func.now()
     )
 
     run: Mapped["NuzlockeRun"] = relationship(back_populates="encounters")
     route: Mapped["Route"] = relationship(back_populates="encounters")
-    pokemon: Mapped["Pokemon"] = relationship(back_populates="encounters")
+    pokemon: Mapped["Pokemon"] = relationship(
+        foreign_keys=[pokemon_id], back_populates="encounters"
+    )
+    current_pokemon: Mapped["Pokemon | None"] = relationship(
+        foreign_keys=[current_pokemon_id]
+    )
 
     def __repr__(self) -> str:
         return f"<Encounter(id={self.id}, pokemon_id={self.pokemon_id}, status='{self.status}')>"

backend/src/app/models/evolution.py

@@ -0,0 +1,23 @@
+from sqlalchemy import ForeignKey, SmallInteger, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.core.database import Base
+
+
+class Evolution(Base):
+    __tablename__ = "evolutions"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    from_pokemon_id: Mapped[int] = mapped_column(ForeignKey("pokemon.id"), index=True)
+    to_pokemon_id: Mapped[int] = mapped_column(ForeignKey("pokemon.id"), index=True)
+    trigger: Mapped[str] = mapped_column(String(30))  # level-up, trade, use-item, etc.
+    min_level: Mapped[int | None] = mapped_column(SmallInteger)
+    item: Mapped[str | None] = mapped_column(String(50))  # e.g. thunder-stone
+    held_item: Mapped[str | None] = mapped_column(String(50))
+    condition: Mapped[str | None] = mapped_column(String(200))  # catch-all for other conditions
+
+    from_pokemon: Mapped["Pokemon"] = relationship(foreign_keys=[from_pokemon_id])
+    to_pokemon: Mapped["Pokemon"] = relationship(foreign_keys=[to_pokemon_id])
+
+    def __repr__(self) -> str:
+        return f"<Evolution(id={self.id}, from={self.from_pokemon_id}, to={self.to_pokemon_id}, trigger='{self.trigger}')>"

backend/src/app/schemas/__init__.py

@@ -17,6 +17,7 @@ from app.schemas.game import (
 from app.schemas.pokemon import (
     BulkImportItem,
     BulkImportResult,
+    EvolutionResponse,
     PokemonCreate,
     PokemonResponse,
     PokemonUpdate,
@@ -34,6 +35,7 @@ __all__ = [
     "EncounterDetailResponse",
     "EncounterResponse",
     "EncounterUpdate",
+    "EvolutionResponse",
     "GameCreate",
     "GameDetailResponse",
     "GameResponse",

backend/src/app/schemas/encounter.py

@@ -18,6 +18,7 @@ class EncounterUpdate(CamelModel):
     status: str | None = None
     faint_level: int | None = None
     death_cause: str | None = None
+    current_pokemon_id: int | None = None
 
 
 class EncounterResponse(CamelModel):
@@ -25,6 +26,7 @@ class EncounterResponse(CamelModel):
     run_id: int
     route_id: int
     pokemon_id: int
+    current_pokemon_id: int | None
     nickname: str | None
     status: str
     catch_level: int | None
@@ -35,4 +37,5 @@ class EncounterResponse(CamelModel):
 
 class EncounterDetailResponse(EncounterResponse):
     pokemon: PokemonResponse
+    current_pokemon: PokemonResponse | None
     route: RouteResponse

backend/src/app/schemas/pokemon.py

@@ -11,6 +11,17 @@ class PokemonResponse(CamelModel):
     sprite_url: str | None
 
 
+class EvolutionResponse(CamelModel):
+    id: int
+    from_pokemon_id: int
+    to_pokemon: PokemonResponse
+    trigger: str
+    min_level: int | None
+    item: str | None
+    held_item: str | None
+    condition: str | None
+
+
 class RouteEncounterResponse(CamelModel):
     id: int
     route_id: int

backend/src/app/seeds/data/evolution_overrides.json

@@ -0,0 +1,5 @@
+{
+  "remove": [],
+  "add": [],
+  "modify": []
+}

backend/src/app/seeds/data/evolutions.json

@@ -0,0 +1,722 @@
+[
+  {
+    "from_national_dex": 10,
+    "to_national_dex": 11,
+    "trigger": "level-up",
+    "min_level": 7,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 11,
+    "to_national_dex": 12,
+    "trigger": "level-up",
+    "min_level": 10,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 13,
+    "to_national_dex": 14,
+    "trigger": "level-up",
+    "min_level": 7,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 14,
+    "to_national_dex": 15,
+    "trigger": "level-up",
+    "min_level": 10,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 16,
+    "to_national_dex": 17,
+    "trigger": "level-up",
+    "min_level": 18,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 19,
+    "to_national_dex": 20,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 21,
+    "to_national_dex": 22,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 23,
+    "to_national_dex": 24,
+    "trigger": "level-up",
+    "min_level": 22,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 27,
+    "to_national_dex": 28,
+    "trigger": "level-up",
+    "min_level": 22,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 27,
+    "to_national_dex": 28,
+    "trigger": "use-item",
+    "min_level": null,
+    "item": "ice-stone",
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 29,
+    "to_national_dex": 30,
+    "trigger": "level-up",
+    "min_level": 16,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 32,
+    "to_national_dex": 33,
+    "trigger": "level-up",
+    "min_level": 16,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 41,
+    "to_national_dex": 42,
+    "trigger": "level-up",
+    "min_level": 22,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 43,
+    "to_national_dex": 44,
+    "trigger": "level-up",
+    "min_level": 21,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 46,
+    "to_national_dex": 47,
+    "trigger": "level-up",
+    "min_level": 24,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 48,
+    "to_national_dex": 49,
+    "trigger": "level-up",
+    "min_level": 31,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 50,
+    "to_national_dex": 51,
+    "trigger": "level-up",
+    "min_level": 26,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 52,
+    "to_national_dex": 53,
+    "trigger": "level-up",
+    "min_level": 28,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 54,
+    "to_national_dex": 55,
+    "trigger": "level-up",
+    "min_level": 33,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 56,
+    "to_national_dex": 57,
+    "trigger": "level-up",
+    "min_level": 28,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 60,
+    "to_national_dex": 61,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 63,
+    "to_national_dex": 64,
+    "trigger": "level-up",
+    "min_level": 16,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 66,
+    "to_national_dex": 67,
+    "trigger": "level-up",
+    "min_level": 28,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 69,
+    "to_national_dex": 70,
+    "trigger": "level-up",
+    "min_level": 21,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 72,
+    "to_national_dex": 73,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 74,
+    "to_national_dex": 75,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 75,
+    "to_national_dex": 76,
+    "trigger": "trade",
+    "min_level": null,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 77,
+    "to_national_dex": 78,
+    "trigger": "level-up",
+    "min_level": 40,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 79,
+    "to_national_dex": 80,
+    "trigger": "level-up",
+    "min_level": 37,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 79,
+    "to_national_dex": 80,
+    "trigger": "use-item",
+    "min_level": null,
+    "item": "galarica-cuff",
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 81,
+    "to_national_dex": 82,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 84,
+    "to_national_dex": 85,
+    "trigger": "level-up",
+    "min_level": 31,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 86,
+    "to_national_dex": 87,
+    "trigger": "level-up",
+    "min_level": 34,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 88,
+    "to_national_dex": 89,
+    "trigger": "level-up",
+    "min_level": 38,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 92,
+    "to_national_dex": 93,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 95,
+    "to_national_dex": 208,
+    "trigger": "trade",
+    "min_level": null,
+    "item": null,
+    "held_item": "metal-coat",
+    "condition": null
+  },
+  {
+    "from_national_dex": 96,
+    "to_national_dex": 97,
+    "trigger": "level-up",
+    "min_level": 26,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 98,
+    "to_national_dex": 99,
+    "trigger": "level-up",
+    "min_level": 28,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 100,
+    "to_national_dex": 101,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 104,
+    "to_national_dex": 105,
+    "trigger": "level-up",
+    "min_level": 28,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 109,
+    "to_national_dex": 110,
+    "trigger": "level-up",
+    "min_level": 35,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 116,
+    "to_national_dex": 117,
+    "trigger": "level-up",
+    "min_level": 32,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 118,
+    "to_national_dex": 119,
+    "trigger": "level-up",
+    "min_level": 33,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 129,
+    "to_national_dex": 130,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 147,
+    "to_national_dex": 148,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 161,
+    "to_national_dex": 162,
+    "trigger": "level-up",
+    "min_level": 15,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 163,
+    "to_national_dex": 164,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 165,
+    "to_national_dex": 166,
+    "trigger": "level-up",
+    "min_level": 18,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 167,
+    "to_national_dex": 168,
+    "trigger": "level-up",
+    "min_level": 22,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 170,
+    "to_national_dex": 171,
+    "trigger": "level-up",
+    "min_level": 27,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 177,
+    "to_national_dex": 178,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 179,
+    "to_national_dex": 180,
+    "trigger": "level-up",
+    "min_level": 15,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 187,
+    "to_national_dex": 188,
+    "trigger": "level-up",
+    "min_level": 18,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 194,
+    "to_national_dex": 195,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 216,
+    "to_national_dex": 217,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 218,
+    "to_national_dex": 219,
+    "trigger": "level-up",
+    "min_level": 38,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 223,
+    "to_national_dex": 224,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 231,
+    "to_national_dex": 232,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 246,
+    "to_national_dex": 247,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 261,
+    "to_national_dex": 262,
+    "trigger": "level-up",
+    "min_level": 18,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 263,
+    "to_national_dex": 264,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 265,
+    "to_national_dex": 266,
+    "trigger": "level-up",
+    "min_level": 7,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 265,
+    "to_national_dex": 268,
+    "trigger": "level-up",
+    "min_level": 7,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 270,
+    "to_national_dex": 271,
+    "trigger": "level-up",
+    "min_level": 14,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 273,
+    "to_national_dex": 274,
+    "trigger": "level-up",
+    "min_level": 14,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 276,
+    "to_national_dex": 277,
+    "trigger": "level-up",
+    "min_level": 22,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 278,
+    "to_national_dex": 279,
+    "trigger": "level-up",
+    "min_level": 25,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 293,
+    "to_national_dex": 294,
+    "trigger": "level-up",
+    "min_level": 20,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 296,
+    "to_national_dex": 297,
+    "trigger": "level-up",
+    "min_level": 24,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 304,
+    "to_national_dex": 305,
+    "trigger": "level-up",
+    "min_level": 32,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 309,
+    "to_national_dex": 310,
+    "trigger": "level-up",
+    "min_level": 26,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 318,
+    "to_national_dex": 319,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 320,
+    "to_national_dex": 321,
+    "trigger": "level-up",
+    "min_level": 40,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 333,
+    "to_national_dex": 334,
+    "trigger": "level-up",
+    "min_level": 35,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 339,
+    "to_national_dex": 340,
+    "trigger": "level-up",
+    "min_level": 30,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 343,
+    "to_national_dex": 344,
+    "trigger": "level-up",
+    "min_level": 36,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 353,
+    "to_national_dex": 354,
+    "trigger": "level-up",
+    "min_level": 37,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 360,
+    "to_national_dex": 202,
+    "trigger": "level-up",
+    "min_level": 15,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 363,
+    "to_national_dex": 364,
+    "trigger": "level-up",
+    "min_level": 32,
+    "item": null,
+    "held_item": null,
+    "condition": null
+  },
+  {
+    "from_national_dex": 433,
+    "to_national_dex": 358,
+    "trigger": "level-up",
+    "min_level": null,
+    "item": null,
+    "held_item": null,
+    "condition": "happiness >= 220, night"
+  }
+]

backend/src/app/seeds/loader.py

@@ -4,6 +4,7 @@ from sqlalchemy import select
 from sqlalchemy.dialects.postgresql import insert
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.models.evolution import Evolution
 from app.models.game import Game
 from app.models.pokemon import Pokemon
 from app.models.route import Route
@@ -118,3 +119,36 @@ async def upsert_route_encounters(
         count += 1
 
     return count
+
+
+async def upsert_evolutions(
+    session: AsyncSession,
+    evolutions: list[dict],
+    dex_to_id: dict[int, int],
+) -> int:
+    """Upsert evolution pairs, return count of upserted rows."""
+    # Clear existing evolutions and re-insert (simpler than complex upsert)
+    from sqlalchemy import delete
+    await session.execute(delete(Evolution))
+
+    count = 0
+    for evo in evolutions:
+        from_id = dex_to_id.get(evo["from_national_dex"])
+        to_id = dex_to_id.get(evo["to_national_dex"])
+        if from_id is None or to_id is None:
+            continue
+
+        evolution = Evolution(
+            from_pokemon_id=from_id,
+            to_pokemon_id=to_id,
+            trigger=evo["trigger"],
+            min_level=evo.get("min_level"),
+            item=evo.get("item"),
+            held_item=evo.get("held_item"),
+            condition=evo.get("condition"),
+        )
+        session.add(evolution)
+        count += 1
+
+    await session.flush()
+    return count

backend/src/app/seeds/run.py

@@ -12,6 +12,7 @@ from app.models.pokemon import Pokemon
 from app.models.route import Route
 from app.models.route_encounter import RouteEncounter
 from app.seeds.loader import (
+    upsert_evolutions,
     upsert_games,
     upsert_pokemon,
     upsert_route_encounters,
@@ -75,6 +76,15 @@ async def seed():
             print(f"\nTotal routes: {total_routes}")
             print(f"Total encounters: {total_encounters}")
 
+            # 4. Upsert evolutions
+            evolutions_path = DATA_DIR / "evolutions.json"
+            if evolutions_path.exists():
+                evolutions_data = load_json("evolutions.json")
+                evo_count = await upsert_evolutions(session, evolutions_data, dex_to_id)
+                print(f"Evolutions: {evo_count} upserted")
+            else:
+                print("No evolutions.json found, skipping evolutions")
+
     print("Seed complete!")
 
 

frontend/src/api/encounters.ts

@@ -1,24 +1,29 @@
 import { api } from './client'
 import type {
-  Encounter,
+  EncounterDetail,
   CreateEncounterInput,
   UpdateEncounterInput,
+  Evolution,
 } from '../types/game'
 
 export function createEncounter(
   runId: number,
   data: CreateEncounterInput,
-): Promise<Encounter> {
+): Promise<EncounterDetail> {
   return api.post(`/runs/${runId}/encounters`, data)
 }
 
 export function updateEncounter(
   id: number,
   data: UpdateEncounterInput,
-): Promise<Encounter> {
+): Promise<EncounterDetail> {
   return api.patch(`/encounters/${id}`, data)
 }
 
 export function deleteEncounter(id: number): Promise<void> {
   return api.del(`/encounters/${id}`)
 }
+
+export function fetchEvolutions(pokemonId: number): Promise<Evolution[]> {
+  return api.get(`/pokemon/${pokemonId}/evolutions`)
+}

frontend/src/components/PokemonCard.tsx

@@ -28,8 +28,10 @@ const typeColors: Record<string, string> = {
 }
 
 export function PokemonCard({ encounter, showFaintLevel, onClick }: PokemonCardProps) {
-  const { pokemon, route, nickname, catchLevel, faintLevel, deathCause } = encounter
+  const { pokemon, currentPokemon, route, nickname, catchLevel, faintLevel, deathCause } = encounter
   const isDead = faintLevel !== null
+  const displayPokemon = currentPokemon ?? pokemon
+  const isEvolved = currentPokemon !== null
 
   return (
     <div
@@ -38,15 +40,15 @@ export function PokemonCard({ encounter, showFaintLevel, onClick }: PokemonCardP
         isDead ? 'opacity-60 grayscale' : ''
       } ${onClick ? 'cursor-pointer hover:ring-2 hover:ring-blue-400 transition-shadow' : ''}`}
     >
-      {pokemon.spriteUrl ? (
+      {displayPokemon.spriteUrl ? (
         <img
-          src={pokemon.spriteUrl}
+          src={displayPokemon.spriteUrl}
-          alt={pokemon.name}
+          alt={displayPokemon.name}
           className="w-16 h-16"
         />
       ) : (
         <div className="w-16 h-16 rounded-full bg-gray-300 dark:bg-gray-600 flex items-center justify-center text-xl font-bold text-gray-600 dark:text-gray-300">
-          {pokemon.name[0].toUpperCase()}
+          {displayPokemon.name[0].toUpperCase()}
         </div>
       )}
 
@@ -55,17 +57,17 @@ export function PokemonCard({ encounter, showFaintLevel, onClick }: PokemonCardP
           className={`w-2 h-2 rounded-full shrink-0 ${isDead ? 'bg-red-500' : 'bg-green-500'}`}
         />
         <span className="font-semibold text-gray-900 dark:text-gray-100 text-sm">
-          {nickname || pokemon.name}
+          {nickname || displayPokemon.name}
         </span>
       </div>
       {nickname && (
         <div className="text-xs text-gray-500 dark:text-gray-400">
-          {pokemon.name}
+          {displayPokemon.name}
         </div>
       )}
 
       <div className="flex gap-1 mt-1">
-        {pokemon.types.map((type) => (
+        {displayPokemon.types.map((type) => (
           <span
             key={type}
             className={`px-1.5 py-0.5 rounded text-[10px] font-medium text-white ${typeColors[type] ?? 'bg-gray-500'}`}
@@ -85,6 +87,12 @@ export function PokemonCard({ encounter, showFaintLevel, onClick }: PokemonCardP
         {route.name}
       </div>
 
+      {isEvolved && (
+        <div className="text-[10px] text-gray-400 dark:text-gray-500 mt-0.5">
+          Originally: {pokemon.name}
+        </div>
+      )}
+
       {isDead && deathCause && (
         <div className="text-[10px] italic text-gray-400 dark:text-gray-500 mt-0.5 line-clamp-2">
           {deathCause}

frontend/src/components/StatusChangeModal.tsx

@@ -1,11 +1,12 @@
 import { useState } from 'react'
-import type { EncounterDetail } from '../types'
+import type { EncounterDetail, UpdateEncounterInput } from '../types'
+import { useEvolutions } from '../hooks/useEncounters'
 
 interface StatusChangeModalProps {
   encounter: EncounterDetail
   onUpdate: (data: {
     id: number
-    data: { faintLevel?: number; deathCause?: string }
+    data: UpdateEncounterInput
   }) => void
   onClose: () => void
   isPending: boolean
@@ -32,19 +33,48 @@ const typeColors: Record<string, string> = {
   fairy: 'bg-pink-300',
 }
 
+function formatEvolutionMethod(evo: { trigger: string; minLevel: number | null; item: string | null; heldItem: string | null; condition: string | null }): string {
+  const parts: string[] = []
+  if (evo.trigger === 'level-up' && evo.minLevel) {
+    parts.push(`Level ${evo.minLevel}`)
+  } else if (evo.trigger === 'level-up') {
+    parts.push('Level up')
+  } else if (evo.trigger === 'use-item' && evo.item) {
+    parts.push(evo.item.replace(/-/g, ' ').replace(/\b\w/g, c => c.toUpperCase()))
+  } else if (evo.trigger === 'trade') {
+    parts.push('Trade')
+  } else {
+    parts.push(evo.trigger.replace(/-/g, ' ').replace(/\b\w/g, c => c.toUpperCase()))
+  }
+  if (evo.heldItem) {
+    parts.push(`holding ${evo.heldItem.replace(/-/g, ' ').replace(/\b\w/g, c => c.toUpperCase())}`)
+  }
+  if (evo.condition) {
+    parts.push(evo.condition)
+  }
+  return parts.join(', ')
+}
+
 export function StatusChangeModal({
   encounter,
   onUpdate,
   onClose,
   isPending,
 }: StatusChangeModalProps) {
-  const { pokemon, route, nickname, catchLevel, faintLevel, deathCause } =
+  const { pokemon, currentPokemon, route, nickname, catchLevel, faintLevel, deathCause } =
     encounter
   const isDead = faintLevel !== null
+  const displayPokemon = currentPokemon ?? pokemon
   const [showConfirm, setShowConfirm] = useState(false)
+  const [showEvolve, setShowEvolve] = useState(false)
   const [deathLevel, setDeathLevel] = useState('')
   const [cause, setCause] = useState('')
 
+  const activePokemonId = currentPokemon?.id ?? pokemon.id
+  const { data: evolutions, isLoading: evolutionsLoading } = useEvolutions(
+    showEvolve ? activePokemonId : null
+  )
+
   const handleConfirmDeath = () => {
     onUpdate({
       id: encounter.id,
@@ -55,6 +85,13 @@ export function StatusChangeModal({
     })
   }
 
+  const handleEvolve = (toPokemonId: number) => {
+    onUpdate({
+      id: encounter.id,
+      data: { currentPokemonId: toPokemonId },
+    })
+  }
+
   return (
     <div className="fixed inset-0 z-50 flex items-center justify-center p-4">
       <div className="fixed inset-0 bg-black/50" onClick={onClose} />
@@ -87,28 +124,28 @@ export function StatusChangeModal({
         <div className="px-6 py-4">
           {/* Pokemon info */}
           <div className="flex items-center gap-4 mb-4">
-            {pokemon.spriteUrl ? (
+            {displayPokemon.spriteUrl ? (
               <img
-                src={pokemon.spriteUrl}
+                src={displayPokemon.spriteUrl}
-                alt={pokemon.name}
+                alt={displayPokemon.name}
                 className={`w-16 h-16 ${isDead ? 'grayscale opacity-60' : ''}`}
               />
             ) : (
               <div className="w-16 h-16 rounded-full bg-gray-300 dark:bg-gray-600 flex items-center justify-center text-xl font-bold text-gray-600 dark:text-gray-300">
-                {pokemon.name[0].toUpperCase()}
+                {displayPokemon.name[0].toUpperCase()}
               </div>
             )}
             <div>
               <div className="font-semibold text-gray-900 dark:text-gray-100">
-                {nickname || pokemon.name}
+                {nickname || displayPokemon.name}
               </div>
               {nickname && (
                 <div className="text-xs text-gray-500 dark:text-gray-400 capitalize">
-                  {pokemon.name}
+                  {displayPokemon.name}
                 </div>
               )}
               <div className="flex gap-1 mt-1">
-                {pokemon.types.map((type) => (
+                {displayPokemon.types.map((type) => (
                   <span
                     key={type}
                     className={`px-1.5 py-0.5 rounded text-[10px] font-medium text-white ${typeColors[type] ?? 'bg-gray-500'}`}
@@ -120,6 +157,11 @@ export function StatusChangeModal({
               <div className="text-xs text-gray-500 dark:text-gray-400 mt-1">
                 Lv. {catchLevel ?? '?'} &middot; {route.name}
               </div>
+              {currentPokemon && (
+                <div className="text-[10px] text-gray-400 dark:text-gray-500 mt-0.5">
+                  Originally: {pokemon.name}
+                </div>
+              )}
             </div>
           </div>
 
@@ -149,15 +191,77 @@ export function StatusChangeModal({
             </div>
           )}
 
-          {/* Alive pokemon: mark as dead */}
+          {/* Alive pokemon: actions */}
-          {!isDead && !showConfirm && (
+          {!isDead && !showConfirm && !showEvolve && (
+            <div className="flex gap-3">
+              <button
+                type="button"
+                onClick={() => setShowEvolve(true)}
+                className="flex-1 px-4 py-2 bg-blue-600 text-white rounded-lg font-medium hover:bg-blue-700 transition-colors"
+              >
+                Evolve
+              </button>
               <button
                 type="button"
                 onClick={() => setShowConfirm(true)}
-              className="w-full px-4 py-2 bg-red-600 text-white rounded-lg font-medium hover:bg-red-700 transition-colors"
+                className="flex-1 px-4 py-2 bg-red-600 text-white rounded-lg font-medium hover:bg-red-700 transition-colors"
               >
                 Mark as Dead
               </button>
+            </div>
+          )}
+
+          {/* Evolution selection */}
+          {!isDead && showEvolve && (
+            <div className="space-y-3">
+              <div className="flex items-center justify-between">
+                <h3 className="text-sm font-medium text-gray-700 dark:text-gray-300">
+                  Evolve into:
+                </h3>
+                <button
+                  type="button"
+                  onClick={() => setShowEvolve(false)}
+                  className="text-xs text-gray-500 hover:text-gray-700 dark:hover:text-gray-300"
+                >
+                  Back
+                </button>
+              </div>
+              {evolutionsLoading && (
+                <p className="text-sm text-gray-500 dark:text-gray-400">Loading evolutions...</p>
+              )}
+              {!evolutionsLoading && evolutions && evolutions.length === 0 && (
+                <p className="text-sm text-gray-500 dark:text-gray-400">No evolutions available</p>
+              )}
+              {!evolutionsLoading && evolutions && evolutions.length > 0 && (
+                <div className="space-y-2">
+                  {evolutions.map((evo) => (
+                    <button
+                      key={evo.id}
+                      type="button"
+                      disabled={isPending}
+                      onClick={() => handleEvolve(evo.toPokemon.id)}
+                      className="w-full flex items-center gap-3 p-3 rounded-lg border border-gray-200 dark:border-gray-600 hover:bg-blue-50 dark:hover:bg-blue-900/20 hover:border-blue-300 dark:hover:border-blue-600 transition-colors disabled:opacity-50"
+                    >
+                      {evo.toPokemon.spriteUrl ? (
+                        <img src={evo.toPokemon.spriteUrl} alt={evo.toPokemon.name} className="w-10 h-10" />
+                      ) : (
+                        <div className="w-10 h-10 rounded-full bg-gray-300 dark:bg-gray-600 flex items-center justify-center text-sm font-bold text-gray-600 dark:text-gray-300">
+                          {evo.toPokemon.name[0].toUpperCase()}
+                        </div>
+                      )}
+                      <div className="text-left">
+                        <div className="font-medium text-gray-900 dark:text-gray-100 text-sm">
+                          {evo.toPokemon.name}
+                        </div>
+                        <div className="text-xs text-gray-500 dark:text-gray-400">
+                          {formatEvolutionMethod(evo)}
+                        </div>
+                      </div>
+                    </button>
+                  ))}
+                </div>
+              )}
+            </div>
           )}
 
           {/* Confirmation form */}
@@ -229,8 +333,8 @@ export function StatusChangeModal({
           )}
         </div>
 
-        {/* Footer for dead/no-confirm views */}
+        {/* Footer for dead/no-confirm/no-evolve views */}
-        {(isDead || (!isDead && !showConfirm)) && (
+        {(isDead || (!isDead && !showConfirm && !showEvolve)) && (
           <div className="px-6 py-4 border-t border-gray-200 dark:border-gray-700 flex justify-end">
             <button
               type="button"

frontend/src/hooks/useEncounters.ts

@@ -1,8 +1,9 @@
-import { useMutation, useQueryClient } from '@tanstack/react-query'
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import {
   createEncounter,
   updateEncounter,
   deleteEncounter,
+  fetchEvolutions,
 } from '../api/encounters'
 import type { CreateEncounterInput, UpdateEncounterInput } from '../types/game'
 
@@ -41,3 +42,11 @@ export function useDeleteEncounter(runId: number) {
     },
   })
 }
+
+export function useEvolutions(pokemonId: number | null) {
+  return useQuery({
+    queryKey: ['evolutions', pokemonId],
+    queryFn: () => fetchEvolutions(pokemonId!),
+    enabled: pokemonId !== null,
+  })
+}

frontend/src/types/game.ts

@@ -44,6 +44,7 @@ export interface Encounter {
   runId: number
   routeId: number
   pokemonId: number
+  currentPokemonId: number | null
   nickname: string | null
   status: EncounterStatus
   catchLevel: number | null
@@ -71,9 +72,21 @@ export interface RunDetail extends NuzlockeRun {
 
 export interface EncounterDetail extends Encounter {
   pokemon: Pokemon
+  currentPokemon: Pokemon | null
   route: Route
 }
 
+export interface Evolution {
+  id: number
+  fromPokemonId: number
+  toPokemon: Pokemon
+  trigger: string
+  minLevel: number | null
+  item: string | null
+  heldItem: string | null
+  condition: string | null
+}
+
 export interface CreateRunInput {
   gameId: number
   name: string
@@ -99,6 +112,7 @@ export interface UpdateEncounterInput {
   status?: EncounterStatus
   faintLevel?: number
   deathCause?: string
+  currentPokemonId?: number
 }
 
 // Re-export for convenience