Are you ready to repent?

maesterlicious

The kind of man that Kaito comes off as upon first appearance is not entirely defining of who he is, but that's probably easy to say of anyone.

At a glance, Kaito is cold and unreceptive to much of anything, usually keeping a scowl on his face as he speaks or listens. He's blunt and has no problems telling people if they're overreacting or simply assuming too much about him, and no one had better speak for him as if they understand him or they'll get snapped at. Preferring to keep his problems to himself, he tends to be incredibly stubborn about the emotional weight he carries at times as well as any physical stress he puts on himself. These are just a few examples of the layers of ice encasing his heart of gold, however.

The most important thing to Kaito is his younger brother, Haruto. Early on in Kaito's life, he gave up his childhood to focus on taking care of Haruto, their mother gone (presumed dead) and their father, Dr. Faker, having left to focus on research to figure out a way to heal Haruto of the disease he'd been born with. Though, being around 9 or 10 years of age at the time, that was when Kaito needed the guiding hand of his father the most, and it affected him greatly. But not once has he ever blamed Haruto for any of it; instead, Kaito blamed their father for not being around when he should have been, and it caused discord between them.

Later, when their father essentially turned Haruto into a soulless weapon, Kaito's anger towards Dr. Faker only grew and he sought out guidance from another boy who taught him how to duel, Christopher Arclight. They grew close, and Chris always pushed Kaito to his limits with the lesson that the duel isn't over until a duelist's life is at zero. It's during this time that Kaito learned to be ruthless when dueling, and it's this very thing that eventually seeped through his entire personality and took over to deal with his anger and guilt over what he would eventually do.

Once Chris left when Kaito was around 15 years old, angry when he found out that Kaito was Dr. Faker's son, that's presumably the straw that broke the camel's back so to speak, and when Kaito finally built up walls around himself to keep people from getting too close and hurting him again. All that mattered anymore was making Haruto better, making sure he could be his old kind and gentle self instead of the soulless killer he became. And so Kaito continued his training, pushing away people that could potentially be friends just to protect himself while only ever showing his kind self to his brother.

Cut to later in his debut episode when he goes back to Heartland Tower where he lives - firstly, there's his meeting with Mr. Heartland who keeps pushing and pushing (with a creepy smile) that Kaito needs to keep doing this if he wants to see his little brother, Haruto, healthy again, no matter how much he feels guilty for having to take the souls of people in the first place. And a few minutes later, Kaito goes to see his brother and looks terrified, then devastated when Haruto asks why people are laughing, that screams are the only thing that comfort him. When Haruto asks if he's strange, Kaito kneels down to hug him and tells him that he's only having a bad dream, that Haruto doesn't need to worry because he'll be the one to awaken him from it.

After this, it's no surprise that Haruto is Kaito's complete driving force, that everything he does and has ever done has been for the sake of his little brother, no matter how much it rubs his morality the wrong way or how much it hurts him physically to do so. If Kaito's angry, if he sees Haruto in pain and can do nothing about it, he acts without caution, even going as far as hurting potential allies in his rage. He's stopped a duel when he was about to win just because Haruto was in danger, and he constantly exhausts himself, pushing himself to his absolute limits for the sake of making sure that he does everything he needs to so that Haruto isn't sick anymore. Haruto is his number one priority, no matter what, and though he's had a moment or two where he's given up, where he's felt as if he just can't fight anymore, all it takes are a few well-said words to get him back up and fighting with twice the ferocity as before.

He's warm, loving and comforting towards his brother, abrasive yet mildly submissive towards Mr. Heartland, and to his prey or anyone that gets in his way, he's a coldblooded hunter, whistling an eerie tune to strike fear into their hearts before he takes their soul in a duel (however, he prefers to manipulate the fear already there thanks to his appearance and entrances than give them that fear through threats).

But let's get a little deeper than that.

When dealing with other people, at least, once he's on somewhat friendly terms with them, he can be incredibly blunt and linefacey, and he's also incredibly genre savvy at some points, being intelligent enough (considering most of the ZEXAL cast are 13-14 years old and he's, well, 18) to identify when something is a trap and being purposely left out of specific episodes much later in the series so he couldn't put the pieces together of a major plot point too soon. Either way, smiles are rare for Kaito unless he's around Haruto, but at this particular point of the series that I'm taking him from, Kaito is certainly softening up. Ahh, the power of shounen protagonists making friends with the main grumpy asshole.

He tends to be incredibly bitter towards certain people throughout the series, but the only one that truly lasts is Mr. Heartland. He's the one that pushed Kaito to do things he didn't want to do, he's the one that separated him and Haruto multiple times throughout the series, and he's the one that has put Haruto through pain on Dr. Faker's orders. Kaito had also been aware that Mr. Heartland had previously been a criminal and had hated and distrusted him for that alone. Though, by Kaito's knowledge at this point, Mr. Heartland is dead.

Kaito's entirely capable of being more friendly, and from this particular canon point, he's well on his way to doing so. With the resolution of what's essentially a family feud gone extreme, Haruto is no longer used as a weapon and Dr. Faker is making an attempt to actually be a decent father to them since he'd failed to do so before then, so Kaito is able to rest a little easier knowing that his brother isn't in any immediate danger. Though, Kaito still needs a little direction, a little help softening up some more and being able to act civilly with others.

Burning blood/soul - Through dueling, Kaito gained the 'ability' to keep himself alive through just his will to survive. Though he's experienced severe health issues throughout the series (somewhat explained below), it's assumed that this strong will has been what kept him alive, and his 'burning blood' has even expelled hallucinatory poison from his system and helped him recover in a matter of seconds. It really is less of some super special power and more just his will alone.

Photon Mode - There isn't quite an explanation for how Kaito's able to do this (I personally assume some sort of implanted biotechnology), but Photon Mode is able to allow Kaito to 'transform' when he's about to duel, turning his usual black coat into a white one and gaining a D-Gazer tattoo. Because of Photon Mode, he's able to hold onto numerous Numbers cards without giving into the effects that amplify hidden desires. However it does put a physical strain on his body from holding so many Numbers at once at one point, causing seemingly permanent effects (presumably a pallor to his skin and stunted growth). If he duels too much and doesn't rest, chances are he could push his body to its limit and die. (image)

D-Gazer tattoo - Basically, this works almost like a regular D-Gazer, but rather than any extra features the device has, like being used as a means of communication between others, it's used entirely just for viewing a duel happening in an augmented reality setting. It has the advantage however, of not being something that needs to be carried around, and Photon Mode isn't required for it to be activated and appear. It appears as a blue design around Kaito's left eye, turning his usual blue eye red instead. (image)

Any other abilities Kaito has been shown to have in the series were able to be performed with technology he was given and he no longer has/uses at this point that I'm taking him from, seeing as they were imperative to his Numbers hunting, and he no longer does that.