I always figured he was supposed to be permanently invisible or just simply likes to walk around invisible. You never know when you have to slaughter a cat-killer that comes around the corner, so it's best to just be ready at all times.

I think this is justified. I mean Khelavaster is in Terinyo, a peaceful village. Cat lord is quite deep in a monster-infested dungeon.

I meant, that I think he might have the same bug that Khelavaster used to have.

But he's a legendary being that can probably rip most of those monsters to shreds ;)

Anyway, I also think this is intentional, but voted "yes" in case it's actually a bug.

He does not always do this. I think he casts it if he fights another monster before you get to him.

Fixed.