I WISH this was a harem. It's a feast at the beginning of a sort of cap-off game, Sei Monmusu Matsuri, that tries to tie a bunch of games together. In this case, this banquest is all the girls of the first 4 Mamono musume games. Would've been so hot to have a dark gaiden spinoff where an incubus MC hypnotizes them/feeds them a love potion and makes them all his love slaves.