I get the feeling hes actually really strong but unluckly met some sort of demon lord and beat it as a e rank but lost his leg not knowing what he fought.
Can the description of the manga be changed from "willfulness of younger sister" to "Tantrum of younger sister"? Cause im not seeing anything but this in in the first chapter.
I always assumed usa hair was black when i read this a long time ago, but after rereading some of the coloured pictures show it white or brown. So what is his actual hair colour?