Mondo isn’t as into the whole capturing Kyoko thing as the other two are he sees it as incredibly dangerous especially with how many vampires she’s known to have killed. He sees it as incredibly foolish and not worth the risk and headache involved with the whole thing, however he doesn’t want to upset his boyfriend so he helps him out regardless. Taka did save his life after all by turning him into a vampire he feels like he owes him his love and loyalty plus he really cares for him.