Is Shinigami in a 16 year old's body. He possesses strong empathy, which allows him to feel the emotions of others, read thoughts, see memories, and pick up imprints of clairvoyance off of inanimate objects.

He came from a traditional family, and was trained in traditional Japanese martial arts. His parents were afraid of his spiritual powers, which they considered freakish and unfit for their heir as well as something that could unfurl the familiar secret; so as a child, whenever he was caught using his abilities and during special days, he was locked in a cellar.

One spring night when he was 13, unable to sleep, he went out under the sakura trees, and stumbled across a murder as it was taking place. The murderer, Muraki Kazutaka, caught him, raped him, and cursed him to a slow death that gradually drained his life over three years, with the logic that "a beautiful boy deserves a beautiful death". Muraki later explains to Tsuzuki that he did have the option of making the single murder a double murder done by a madman, but instead decided to draw out Hisoka's death painfully; this was done by the curse, taking the form of an incurable illness. This curse is still visible in the form of red marks and symbols all over Hisoka's body, which seems to only appear when Muraki is nearby or active. It has been implied, though not explicitly stated, that the curse will only disappear after Muraki's actual death. After Hisoka died, he became a Shinigami to investigate about his own death, since he had no memories of the event. It is only later we learn that Muraki had since sealed off Hisoka's memories in order to keep his crimes safe from discovery.

In Meifu, Hisoka was assigned as Tsuzuki's partner. Hisoka enjoys reading, and spends much of his time at the library by himself. His health even in the afterlife does not seem to be particularly good, as he has a tendency to faint from heat, lack of sleep; and from drinking alcohol. Also, he is not very strong, as he doesn't build muscle well. However, he is a capable detective, and clever in subterfuge.

Although extremely reserved to the point of coldness, Hisoka deeply cares about other people. When Tsuzuki regains his suicidal tendencies, Hisoka comforts him and ends up saving him from himself. Hisoka also has a strong urge to take care of Tsuzuki, even though Tsuzuki drives him crazy sometimes. He maintains comfortable relationships with the rest of his coworkers, with the noticeable exception of Saya and Yuma, who constantly try to play with him like a doll.

Besides his empathy, Hisoka has also been trained in basic ofuda and defensive magic by Chief Konoe. Later in the series, he goes to seek out a Shikigami for himself in order to increase his power. Hisoka's first Shikigami is a Spanish-speaking potted cactus named Riko, a defensive and water-type Shiki. Hisoka is also adept in traditional martial arts, particularly archery, and kendo.