Neko no Te datte Yaku ni Tatsu - Ch. 235 - Monster

[jonsmth]

Wait, so we didn't get the explanation about Tiggy, did we? We only get confirmation about the bakeneko things and that Mii chan is a hafu; but not how tiggy was turned into one and lost his power later.

If they are bakeneko in the classical sense, they are magical in nature. Animals and even inanimate objects become youkai with enough magic (faith, gratitude, grudges, demonic power, etc) You could say Tiggy is more of an original bakeneko than the owner and Mi's father is.

Instead of generations of faith or strong negative feelings, he got enough power from someone, and it's perhaps driven by Tiggy's own feelings of wanting to survive. When he got into a comfortable and safe environment, he kinda lost that drive so he's just a regular cat now.

I'm guessing that's how it is if they're not gonna go on an exposition about it with some revisionist mythology. The readers likely are expected to have some familiarity with Japanese mythology.