I mean, im also here, I'm a Mashle supporter (I would even say THE, hehe), lay it on me.
He powers up in response to his opponent eclipsing him, it's just him holding back less and less, and then exerting himself at his max output. There isn't any requirements, it usually just happens along with his muscles expanding or eventually him just... exploding a bit I guess?
Eh, it's a conscious effort to hold back less and less, and he announces his percentages when fighting, but it's basically instant. It's apart of his master cane, allowing him to put more magic into it to gain egregious physical boosts.
That's the thing, Doom can regenerate any grievous injury that he might take. Thanks to his Devil Heart, he has the same level of regen as say, his brother Delisaster, who despite getting his head cleaved straight in half, he could regenerate it pretty quickly.
No? Why would it? Again, Doom has the same level of regen as his brothers, who are able to regenerate their brains getting cleaved.
Yeah, he typically uses it for fun to clash physically, or to flip people around like pancakes
