@Marco_Hueber judging from everything so far his magic is closer to 1,000,000,000,000,000 AKA 1 quadrillion, Pazuzu is closer to ten million (a very rough estimate that only works if the MC's brother is at 1000) so comparing "auras" gave me that number
@Moderate-Reader I've always laughed at this kind of analogy. if it's 99% then that means he receives a slight amount of damage from even the weakest of spells cast from the most basic of beginners. "absolute resistance except to the highest of tiers" would make more sense or, as is in this case, "cannot receive damage from magic that is less dense than the magic that makes up their body." Since Majins are suppose to be beings of pure magic, the thought of coming across a denser form of magic from something that isn't a direct source wouldn't even seem fathomable, especially from a human child.