[@Sarcelle Renard]I'll make it so that if he's decapitated, then he will die like most would. But I'm curious if this would just be for rank B?

As for his learning, maybe if he's exposed to the ability a certain amount of times. Like 10 times? Exposure is suffering, so he'd literally have to be struck by the attack/affliction. And maybe for rank B he can learn up to 4 abilities?

Because if he has a limitation on learning abilities meaning they just vanish overtime, then he doesn't ever have any abilities and the ability section remains empty. Therefore, he might as well be rank B forever.