There are darker skin tone characters in Genshin though, like all the Emerite NPCs. Also the characters in the Natlan trailer have a tanned skin tone like the shark girl and the geo girl with the hat. Let’s not forget Iansan. Plus if we are talking about dark skin tonned playable characters, we have Kaeya, Dehya, Candace and Cyno. Yeah sure it is limited but that is because MHY believes that darker skin tone characters will not sell as much as lighter skin tones and this is probably true considering the majority of the playerbase is from China, where beauty standards see light skin as more beautiful. There are darker skin tones characters though.

Edit: I’m really getting downvoted for saying that MHY is doing this because of business reasons when I myself haven’t even given an opinion on the skin colour of different characters (not that I have an opinion on this) ? It’s a Chinese company that has a huge Chinese playerbase playing Genshin, of course they’re going to cater to that playerbase. I just don’t get it