BoBoiBoy x Fire Emblem: Three Houses Crossover

With all of his friends defeated and Retak'ka absorbing 5 of the 7 Elemental Powers, BoBoiBoy makes a final stand. Their ensuing battle creates a portal that takes them to the land of Fodlan.

Rules:

House of choice (Black Eagles, Blue Lions or Golden Deer) is up to the challenger

Takes place during BoBoiBoy: The Movie 2

BoBoiBoy is a young adult

 BoBoiBoy x Female Byleth pairing

Optional:

 BoBoiBoy x other female pairings

If Black Eagles route is chosen, Retak'ka joins forces with Rhea/Seiros