Responses
Looks like he is as straitlaced as Kalego-sensei thought his brother was (that Narnia embodied the Naberius vow to be protectors more than anyone in their family).
He wanted to protect his brother when he was young (thus, the deception) and ultimately the current demon world.
he's not on iruma's side but he's also not iruma's enemy. he just wants what he think is the best for the demon world. at least someone who not only think for himself.
I think he can be negotiated with if iruma and friends can show that iruma being here has more benefit than not, and that iruma can protect himself from demon who wanted to use him for something bad.