I enjoy playing kemopop on mobile, although I already purchase steam ver., but I still prefer to play the android ver., so I wonder if itch.io remove kemopop one day, can we still buy/update it some where else úwù?

It's something I've been thinking about. I was thinking about making an android depot on steam, but I realised it's not a good idea for a few technical reasons. 

For now, I don't really have an answer. Without itch, there's no real storefront for 18+ android titles.

sorry to hear about itch hitting you as well. it's targeted all of us creators of the weird, and your work is some that really inspired us. We didn't know there was  steam version we will look into purchasing that to help support you. Good luck with the game dev. XD