[quote=@VitaVitaAR]
[@Enkryption]: Mmm, Akitsushima is the setting's Japan equivalent and is not connected to this continent, and it doesn't have harpies.
[/quote]

This feels like such a small detail. Species move. Birds are migratory; they fly across entire landmasses and oceans to settle seasonally. There's no reason that the Karasu couldn't have migrated from their home continent and settled there; some opting to stay behind, and assimilate into the new culture - becoming a new people, settlers.

Humans do that, literally, all the time. And, they don't have the added benefit of WINGS to fly with.