The fact that the society in Inazuma is the same as it was 500 years ago is very telling. Despite a few hiccups, like Ei's first failed puppet everything has been more or less good. Until now that is.
First; This is NOT a fighting fic. The main character has an special ability that lets him do and see things nobody else can do, but that does not mean he is going to destroy Teyvat. He can see souls and seal or manipulate them, but he needs to touch the person, and even that has limits. Imagine trying to seal the Raiden Shogun, only to get fried just touching her.
"Sure," Ren nodded. Then the little girl cheered and ran to the TV, changed the channel, and soon the TV blared, "Magical girls! Before my tentacle king, you will all be XXX by me! Watch the world be destroyed by my tentacle demon king! Mwahaha!"
He hated everything about them, he was filled to the brim with hatred for the disgusting beings. They were unnatural, no not only unnatural they were vile and cruel.