Chapter 114: Origins gone
There's nothing worse than a random girl coming out of nowhere with a child, telling you that you're a father and should pay child support. The only worse thing would be if that girl came to you with quite a big child, meaning she only came to you because she lacked money.
Leon was in a similar situation right now.
He ended up in a mini-world of his relatives that had grown so attached to their peaceful world that they became insecure to the point where they would sacrifice their far relatives. Leon also came here out of nowhere, not expecting that his family was actually bigger than he thought, and from a fantasy world, at that!
But since it was so easy for them to give up on him and simply enslave him in a different world, Leon also didn't have problems killing them all. He only aimed his powers at those who barred his way as even in his current state, Leon didn't think of killing everyone in this mini-world.