As a result of his grandfather's violent attempts at subduing his unruly nature, little Mello was extremely defiant towards authority and quick to turn to verbal and physical aggression. As he gets older, his moods remain just as volatile but he learns to (mostly) manage his anger, a feat often accomplished by sublimating it into delightfully vicious fantasies.

Has always been utterly fascinated by torture, loving nothing more than to learn all about its history, different types and techniques. He never really planned to use that knowledge on anyone (although it's probably come in handy at some point in his mafia era, let's be real), the only times he's enjoyed tormenting someone (outside of a bdsm session) have been when he's subjected Matt to horror literature exposure therapy back in Wammy's.

Has daddy issues. In the way he blames his mother unaliving herself on his father disappearing on her. He still holds onto vengeful intents towards him, wonders if that'd finally cut whatever tie he might still have with such a dishonorable individual, or if then he'd simply be the only one left to blame.

As part of his inferiority complex, deep down he really believes he's wicked, hated by God, with no hopes to succeed in anything good or be saved. Upon seeing them for them first time, he can't help but think that the burns are the manifestation of his curse, his own undeniable mark of Cain.

Very manipulative, we know, but the thing is he doesn't do it on purpose. He just can't stand to even risk being controlled, coming out on top is a priority in relationships, too, so his default approach is to read people like books, dangle anything they want in front of them and get them to do his bidding. Does he like them? Does he hate them? Doesn't matter: once done with them he'll leave them in shambles anyway! (If they're lucky)

Speaking of which... Mello's a genius, not an assassin. His original plan for that one mafia boss was never to take him out himself, but rather to groom the guy's malcontent son to do the dirty work. Which the young man did. Only to come back home in a confusional state twenty minutes later to Mello decapitating daddy's corpse– thus becoming his first kill. Shortly followed by mommy. Then Mello finished the job, put his backpack in the freezer and took a bath in the jacuzzi to make himself presentable again before leaving.

Rankings meant next to nothing to him. Sure, he enjoyed the popularity and vague sense of accomplishment that came with being first, but what really convinced him to risk disastrous reactions on Mello's part as impeccable results piled up was the thought of keeping the game going between the two of them, and Mello's attention on himself.

Probably because of his inclination towards philosophical thinking, it's a rarity for him to care about anything or anyone much, but when he does it affects him deeply and forever.

A perfectionist, but not in the toxic way. It's just that he can't be happy half-butting things that are in his power anyway, everything needs to be curated down to the tiniest detail!

Knows that people tend to dislike him and his answer to that is to find them annoying first, and possibly snark them, you know, as a treat.

Serial collector. The moment he gets two of anything the instinct kicks in.

Sucker for occultism.