So his muscles are immune to magice... strange... I could swear that magic attack hit his HEAD, too.
And The brain is NOT scovered by muscles on top but only by the skull = bone, meat, skin and hair.
So that hit should have been deadly...
Well, reading one chapter to know that the story does not make any sense will spare me from having to read any further before realizing that and stopping to read it.
This lets me quit right here and now.