Star Ocean
There are quite a few JRPG series that would be perfect for a Musou game, but Star Ocean would definitely introduce a unique style we haven’t seen from Koei Tecmo. The action-focused combat system already gives characters a slew of different special moves and combos, easily adaptable into a Warriors combo system.
Every party character in each Star Ocean game also has a unique fighting style, meaning tons of variation. The series’ mix of fantasy and sci-fi has always been one of the main draws, and a Musou game could feature a story that has a party of characters planet-hopping, maybe after some catastrophic space-time event has pulled everyone together. Considering where the stories of some Star Ocean games have gone, this wouldn’t feel out of place.
