Demon Slayer: I'm Just Hungry

A quick heads-up: this story has quite a few elements, so if you can't handle that, leave now before you laugh yourself silly. Also, it includes some things from Mihoyo's works, so please don't complain. I did say at the beginning that characters from Genshin Impact and Honkai Impact 3rd would appear. This is a world where demons exist, and it's not a happy one. We have no way of knowing how demons came to be or why they eat people. The story mainly follows an ordinary boy with an ordinary beginning, and his happy life with his little System. Uh, there are some very interesting stories, as well as sad ones. The usual tropes are here, too. Oh, and last, last, last of all, the feast is already planned. It's just that the resistance has been a little fierce lately.