He is voiced by Jun Fukuyama in the Japanese version of the anime and Eric Vale in the English version.
Kazuma appears to be in his late teens with short brown hair and dark green eyes. He wears a pair of thick-rimmed glasses, and is normally seen dressed in his uniform. In his Regalia form, he appears as a cherry blossom-shaped earring. Before becoming a Blessed Vessel, his Regalia form was of a small thorn/nail.
Kazuma is a calm, serious, and sensible person. He cares greatly for Vaisravana/Bishamonten, calling her by a pet name, "Veena", as well as his fellow Shinki. He is also shown to be extremely loyal to his master, as well as responsible and trustworthy. He also honours his debts, particularly to Yato. He is polite to everyone, regardless of whether he is stressed or not. While loyal to his master, he is also loyal to Yato as he helped perform Yukine's ablution to save Yato and protected Yukine from Viina due to the fact he begged Yato to slay his fellow shinki to stop their blight from affecting her.
He is a kind person in general and a good teacher, as he willingly teaches Yukine some techniques as his fellow blessed shinki. Despite his serious nature, he is shown to have a comical side. While using Bind on Yukine to help him practice to use the technique and develop his defense, each time Yukine lost he drew on his face until he looked ridiculous. On another occasion, in chapter 40, when he and Yukine were practicing using shinki techniques, Yato mentioned how Kazuma had a horde of Bishamonten photos and admitted to supporting Yato since day one without feeling guilty, causing Viina to beat both Kazuma and Yato up. the fact that he has so many photos of her, even on his smartphone as mentioned in chapters 38 and 39, heavily implies he has feelings beyond a master and servant and that he holds her in a romantic regard but doesn't act on those feelings, possibly since he feels that would infringe upon their relationship as master and servant, her status as a God in contrast to his lower status as a shinki, and the fact that, as stated in chapter 7 of Noragami Shuushuu the seven gods of luck are not allowed to get themselves involved romantically.
In some ways he is somewhat similar to Bishamonten as he is shown to hate Nora like most characters of the series and as a result hated the idea of having to bow to a Nora to save his master (as Yato's only shinki at the time was Nora) just as how Viina hated Yato because he saved her twice and how she couldn't protect her two shinki clans and had to rely on a no name God to save her. He also admits he felt he is worthless because after asking Yato to slay the Ma clan, he was going to reveal his treachery to Bishamonten but when she told him she only needed him he felt a sort of happiness hearing that and decided to let her continue hating Yato so she could heal.
He admits he felt good being needed and just wanted her to smile but after seeing the destruction she caused (influenced by Kuguha) he felt he failed as her blessed vessel because he made her upset a second time. He continues to think back to Bishamonten's first leads words when Kazuma was a nail about how Kazuma was a bad omen since he pierced Bishamonten's body, though Bishamonten assures him that she still wants him to follow her. He has even stated in episode 4 of Noragami Aragoto when he asked Yato to kill the ma clan that only Bishamonten owns his name and in chapter 25 when Ebisu tries to buy Kazuma saying it is alright if Kazuma is a stray because he values Kazuma's skills, Kazuma states the only one he wants to protect is Bishamonten, causing her to blush.
- Borderline: Like all Shinki, Kazuma has the ability to create a Borderline, though he struggled with it at first.
- Tracking: Kazuma is exceptionally skilled at tracking people, gods, and their Shinki. He is also a skilled navigator.
- Umbra: Kazuma has the ability to manipulate his surroundings. He was able to make it so that Vaisravana and Kuraha were unable to see Hiyori.
- Restraint: Kazuma has the ability to cast a binding restraint on a target with a power equal to or less than his own. This ability appears to take the form of invisible chains.
- Resound: Kazuma used this spell on Kugaha in an attempt to get him to say who he was working for. He used this on Yato but found it ineffective. He used this skill again to make Yukine talk unwillingly. However, Yukine was able to break the spell.
- Domination: Kazuma has the special ability to connect with other shinki, he can either guide them (like he does with Vaisravana's other shinki) or he can attack (like he did with Kiun, in his form of a serpentine dragon made of lightning). It is shown that he can take domination only if he believes so.
Spell/Chant/Song: It enables him to cast spells that can be used as protection or to attack; in the manga, he uses this to help Yato in his fight (chapter 65)