In order to help fuel interest and discussion, here are some sample Character Flaws you could expect to get. It should at least signify how dysfunctional you can expect your character to be. These are only demonstrative examples, not necessarily specific traits you'll have yourself; you could instead of the below have an unhealthy obsession with saving people from dire circumstances or martyring yourself on metaphorical (or maybe literal) crosses, and more in that vein. Either way, you're some flavor of crazy.
Character Flaw: Brutal - You are not merely unbothered, but even exult in violence, eager for excuses to indulge as if it were a narcotic or a favored pastime. There is something musically beautiful about - not strife, not martial attainment in the sense of combat sports - but rather the simple event of a human form meeting with pure destruction, a skull shattering as it encounters your fist. You find hurting others vaguely satisfying, even while being hurt yourself still inspires vengeful sentiment. You find those who do not share this view contemptible, lacking a spine, and your esteem towards them diminishes as a consequence; an attitude which borders on disdain for the weak.
A minor variant: While you continue to find violent actions pleasant to indulge in, you understand this urge is not necessarily shared by others and do not find them any more contemptible. While you may still wish to solve problems violently and might even lose yourself momentarily, it'll never become an overwhelming or overriding feeling.
Character Flaw: Hubris - You find other beings rather tiresome and dull; not necessarily more difficult to empathize with, but simply... annoying, like you're not sure if you can find a reason for them to even exist. At best, they are amusements or very irksome sources of danger; at worst, they're infuriating obstacles to getting what you want. Even those stronger than you are people you roll your eyes at behind closed doors; nothing more than temporary roadblocks on your ascent. You were chosen after all, and you know as a matter of fact you're better than that bunch of nobodies. What a better world it'd be if they could conveniently line themselves up so you could kill them without putting in too much effort. Oh well, you suppose you'll have to earn your crown with hard work - shame they couldn't see your self-evident greatness the way you do.
A minor variant: Albeit tending towards self-assuredness in your resolutions and decisions, you do not find it any easier to deride others. Your sense of self-worth is slightly inflated, but not downright narcissistic.
Character Flaw: Death Addict - This is not suicidal or genocidal ideation; rather, the very idea of death excites you, in a completely different way than most people could ever hope to imagine... Ever since you were a child and saw your first corpse, you understood the concept of death was somehow special to you. You seek to incarnate your own ideal of death, a grim reaper avatar, so that you can marry Death Itself - the only bride ever worth contemplating. Naturally, it helps to show death your appreciation on the way there, by flirting with it as often as possible! You will make sure to frequently become embroiled in deathly dangerous affairs and to murder acceptable targets regularly.
A minor variant: You find dead bodies and morbid imagery to be unusually fascinating and will seek to reasonably incorporate them where you can. However, you are not literally on a quest to create a body into which the concept of death can incarnate itself so you can date it.