Ughh, I always hate the trope where the strong kid is so confident. I’m expecting things like “oh, how long will you last before you break” or “my last toy broke quite easily, I wonder how long you’ll last” from that kid.
Anyhow, this series is just “eh” so far. Another thing of note is that you’d think that people like a priestess, sage, or a hero would have high resistance to mental attacks, but I suppose demons are just that strong huh, even though this sage just obliterated them.