Kyusen

Simple, give the jacket to Asia, and give his shirt to Koneko(lowers chance of severe beating that may follow) Akeno would get off on the denial and Rias can take it as punishment for being spoilt(plus they both probs have clothes spell of some sort)

Yh, some of the old ones where good. Especially like the slow corruption of the cinnamon roll nun.

Can’t remember after all this time

Also depends on which mythical creature it is, as some you have to either completely destroy or maybe pierce its heart or destroys it core.