Player Class
Pokemon D&D 5e
The player's character now counts with their own class. They earn levels to progress their class and gain new skills.
Level Progression
The player gains a level, approximately, for every 4th Pokemon they catch. The exact progression table/formula needs to be refined.
caution
Revisit the level progression, as a more "Tears of the Kingdom" approach might feel more natural than a plain "Skyrim/Fallout" approach to this