Hang on. Isn't Nagumo like resistant to debuffs or some shit? Might have to reread on the treasures he got.
EDIT: nvm... It was NOT the treasures he got. The resistances to basically any debuffs came from those monster meat he ate. He's got lightning, poison, paralysis, petrification, fear, elemental. You can have a look at chapter 7 page 15.
He got:
[ul]lightning resistance from eating a lighning wolf.
petrification resistance from eating a small lizard that petrified the remainder of his left arm stump
poison from a basilisk
paralysis - not too sure what he ate to get this one. could probably come from basilisk too? or the six legged cat he ate? or owl?
elemental - not too sure what he ate to get this one[/ul]