Kuro is a fairly attractive, tall young man with light skin, black hair, and yellow eyes.
Kuro is quiet and tends to be very nonconfrontational, barely even taking notice of his own injuries. He is uncaring about his own safety due to his healing abilities.
When he was a child he grew up in a traditional Japanese house with his many relatives. One day while eating with the rest of his family, the rest of his cousins and possibly siblings, seem to collapse and die within seconds of eating. His grandmother reveals that he had been fed both Kudan and Ningyo meat as part of the Sakuragawa family's goal of creating someone who could predict the future without dying. He was one of the only ones who survived, alongside his cousin Rikka.
He leads a relatively normal life as a high schooler, even finding a girlfriend, Saki Yumihara, and later going to the same college as her. During this time he also visits Rikka at the hospital she admitted herself to, going regularly enough that the nurses know him and Saki goes with him to make sure they don't flirt with him. He was a second-year at H-university and a student at their law school.
Eventually, Saki finds out the truth of what he is after the two come across a kappa after visiting a shrine and the kappa flees in fear. This prompts her to break things off with him and move away to another city for work immediately after graduation.
Immortality: Kuro has been granted the ability to recover from any physical injury. First demonstrated when encountering the Bull Ayakashi, he lets his own arm to be eaten by Yokai. Kuro however heals it within seconds, in addition that his flesh is also a poison for the Yokai. During his first fight against Steel Lady Nanase, Kuro got his head completely crushed by the spectre, only to regenerate immediately, repairing the brain and nerve cells to keep his mind intact. His healing factor can work both as regrowth and reversion: when he got his arm eaten, Kuro regrows his missing arm, however when his ear was ripped off by Steel Lady Nanase, it simply returned to him, undoing all the damage.
Precognition: Kuro's another ability is to predict the future. While the price to use this ability is "death", Kuro is immune to this since he has acquired immortality. First demonstrated when he manages to forecast the Steel Lady Nanase's attack, quickly countering the spectre. It is later revealed, rather than a prediction of the future, out of the infinite branches of time, Kuro can choose one and that is what will happen, effectively determine the future. Despite this, the power is limited to the branch he can grab.
Superhuman Strength: Kuro is much stronger than any normal human, strong enough to hold his own against Steel Lady Nanase.
Kotoko Iwanaga: The two first met shortly after Kuro had broken up with Saki, which Kotoko decided to make the first move. Several years later, the two date, but Kuro continues to hold only platonic feelings for Kotoko. Despite so, Kuro cares for Kotoko's well being and will protect her when needed. However over the course of the series, Kuro began to develop actual romantic feelings for her, later telling her in Chapter 13 that he needed her. It has also been alluded on several occasions by Kotoko that she and Kuro have done erotic things, though Kotoko says this mostly just to taunt Saki.
Saki Yumihara: Saki is Kuro's ex-fiancé who broke up with him after he reveals his powers to her. They stopped talking after that, but their reunion several years later rekindled their friendship.
Rikka Sakuragawa: She is Kuro's cousin and his "first love. "He deeply cares for her and would often visit her in the hospital.