In regards to Nintendo copyright:
There's precedent for Pokemon fan games (rom-hacks and even a custom framework called Pokemon Essentials people use for RPGMaker XV) as well as Pokemon hentai (look anywhere on the internet). Nintendo obviously has rights to characters/assets/etc but the legality for software is a bit more complicated than "they're using my character! sue them!" (at least in the U.S., idk where creator of this game is, but Itch is in the US)
Generally, Nintendo will sue if someone's directly selling something for money, since the illegality is much more obvious. If this game remains free to download (Patreon notwithstanding) with it's updates, it's just a piece of software like any other Pokemon fan game.
Not to mention there are plenty of adult games out there with Pokemon characters. It's been this way since Day 1 of Newgrounds.com.
Just wanted to clarify this since someone below made a comment about this being some make or break to invest in this game's Patreon, which is pretty stupid. Support the creator if you like the game and want what they're offering, don't if they're not.
TO GIGACHILL: Patreon is probably responsive to cease+desists, so I'd move to SubscribeStar if possible. Regardless of legality/illegality, private companies are assholes, and Patreon has been cracking down on virtually anything it can justify lately. SubscribeStar will probably earn you less money, but it protects you from the risk of suddenly losing all your income. Plenty of creators (IE Selebus, who is a pretty large VN dev) have had this happen to them.
This is a pretty impressive game so props. Hope you keep developing it and do well.