27level cap
Duane (party 1: your first visit) fields 4 Pokémon between level 25 and level 27 in Hepatica Gym.
This is around Hepatica Town — Duane and the Skull Badge in the story — that page lists everything you can have caught by this point.
Types on this team: Dark ×3FireFlyingGhostPoison
| Pokémon | Ability & item | Moves | Base stats | |
|---|---|---|---|---|
 | Nyanell Lv 25 Dark | Faint Attack Fury Swipes Growl Swagger | HP60Attack90Defense60Sp. Atk65Sp. Def55Speed110Total440 | |
 | Murkrow Lv 25 DarkFlying | Night Shade Pursuit Wing Attack Swagger | HP60Attack85Defense42Sp. Atk85Sp. Def42Speed91Total405 | |
 | Haunter Lv 25 GhostPoison | Hypnosis Curse Night Shade Swagger | HP45Attack50Defense45Sp. Atk115Sp. Def55Speed95Total405 | |
 | Houndoom Lv 27 DarkFire | Bite Smog Flame Wheel Swagger | HP75Attack90Defense50Sp. Atk110Sp. Def80Speed95Total500 |
How to beat this team
Shared weaknesses. Fairy hits 2 of 4, Fighting hits 2 of 4, Ground hits 2 of 4, Rock hits 2 of 4.
Level to be ready for. Lv 27 — Houndoom, the highest on the team.
Fairy Pokémon you can have caught by this point. From this guide’s own encounter tables, by Hepatica Town — Duane and the Skull Badge: