demon (megami tensei)
The recruitable demons/creatures/deities/historical figures from the Megami Tensei franchise. They are featured in the mainline series (Shin Megami Tensei), and spin-off series/games (Persona, Devil Summoner, etc.)
See: List of Shin Megami Tensei demons for a list of them ordered by the race they typically appear as in the mainline games.