Kaito Kurui/Tropes

A-G
A God Am I: Kaito outright admits toying around with the lives of others is like playing God, and he very much enjoys it, thus making him a borderline example.

Badass Bookworm: He looks unimposing and prefers being a scientist over a warrior, but he's also a highly effective combatant.

Composite Character: Kaito shares multiple traits with both Kisuke and Mayuri; Kisuke's general sly behaviour and manipulation behind the scenes, as well as Mayuri's "mad scientist" nature and general disregard for human rights and well being.

Creepy Good:  With "good" being rather subjective with Kaito, he is, once again, still sided with the "good guys", however, the fact that he is very secretive, enjoys cutting into bodies and the like, and has no qualms about suggesting..."modifications"...he can give to one's body really do give him an unnerving edge. He enjoys this. Quite alot in fact.

Expy/Identical Stranger: Kaito looks nearly identical to Kokutō (minus the burns), right down to the turban. If you put them side-by-side, they could be twins. This resemblance is intentional on the artist's part, and Darkrai himself was a fan of Kokutō.

Gadgeteer Genius:  Kaito spends his time inventing things left and right, and is responsible for immense research into the use of Reigai.

Good Is Not Nice: Well, he is affable enough, but he tends to be extremely manipulative.

H-P
Forgets To Eat: Kaito, apparently, gets so wrapped up in his work that he often forgets to have meals. Considering it's Nika who cooks for him, whether this is wise or not on his part remains to be seen.

Immortality: Kaito is of the Spare Bodies variety of immortality, through a device he created. Kamehame Hadoken: Kaito, due to his extensive research, is capable of performing the Cero.
 * Body Backup Drive​: What the Kisōkai Kaito created entails. Kaito is capable of switching himself or anyone who requests it into another, fresh body should it so be required, effectively extending their lifespan through the use of the machine.
 * Brain Uploading: Pretty much what the process is. Through the use of multiple wires, the target's conciousness is downloaded from their body and transferred directly to the waiting Reigai. In most series', a "soul" transfer would make more sense, but a spiritual being is already a soul, and thus, "conciousness transfer" was the work-around.

Mad Doctor: When he's not busy being a Mad Scientist, he's busy being a Mad Doctor instead.

Mad Scientist: Kaito is this to the core. He very much enjoys his job, many of his procedures can be described as something akin to torture, he has a secondary laboratory underneath his first one that he has told no soul about, and it is here where his more menacing experiments take place. And let's not discuss the horror that is the Nōmutsuru.

Never Bareheaded: With the exception of sleeping, Kaito never removes the turban he wears that wraps around most of his head and his right eye, concealing the Usominuku passed down in his family.

Nice Guy: For what it is worth, Kaito, unlike Mayuri, isn't rude or even outright malicious, you could even have a cup of coffee with him and have a nice chat.

Ninja Pirate Zombie Robot: Samurai Mad Genius Gadgeteer Genius Shinigami

Omnidisciplinary Scientist: Like Mayuri and Kisuke in canon, Kaito seem to have skill in various scientific fields, however, if the reigai, as well as his many other bodily manipulation experiments are anything to go by, Kaito seems to favour biology. He is, however, skilled in engineering, or at least the Soul Society equivalent of engineering, which is how he's created several different items and can wear both the "eccentric inventor" and "mad scientist" hats quite nicely.

Pet the Dog: Sort of. Despite the fact that Kaito enjoys toying with bodies (living or dead, he really doesn't care) as much as Mayuri does, just like Mayuri, Kaito is still just...a guy. Several examples of this kind of behaviour can be seen with Nozomi, the Reigai he created modeled after a Shinigami from his Division who died and he had a close relationship with. In other instances, he actually saves Ahatake's life and helps him try and save Harumi to prove her innocence, gaining nothing from this himself. Finally, he funds a joke store in the Rukongai where children can purchase toys for very low prices. He's not all that bad when he's not cutting you open.

Power Fist: Kaito's Zanpakuto, sealed or unsealed, takes the form of a gauntlet he wears on his right arm.

Power Perversion Potential: Darkrai noted that MANY of Kaito's inventions have sexual undertones. An army of women, an orb meant to be swallowed, false bodies, a bondage chair, a mind-control device that is extremely invasive, etc.

Psycho for Hire: Kaito just hides it. Really really well.

Q-V
Refuge in Audacity:  Kaito is well aware that he is a sociopathic madman with a silver-tongue. He just doesn't care.

Science Hero: Science Nominal Hero at best, but Kaito is technically on the side of "good guys" and he is the resident Mad Scientist.

The Starscream: Darkrai likes to joke that Kaito is secretly planning a coup on Soul Society. But honestly...why else would he be doing everything he does, if not gearing for war?

Trademark Favourite Food: Kaito appears to have a liking for coffee, despite it not being something found in the Soul Society, he procured it from the World of the Living and has since developed a taste for it. This actually a nod to Lamia, a character made by Bounty that Darkrai happens to be fond of,

W-Z
White-Haired Pretty Boy: For someone so friggin' insane, it doesn't exactly show on Kaito's face.