Kite Tenjo is an eighteen-year-old Number Hunter and a central figure in the story. He is driven by a singular, powerful goal: to save his younger brother, Hart Tenjo. Dr. Faker, the boys' father, led Kite to believe that the mysterious Number cards were the cause of Hart’s illness, and that collecting them was the only cure. To accomplish this, Kite hunts down those who possess these cards, forcefully extracting both the Numbers and their owners' souls using a special ability called the Photon Hand. He is accompanied by a loyal, if often overeager, robot named Orbital 7 who assists him in his hunts.

In his pursuit of Numbers, Kite is ruthless, precise, and often cruel. He announces his arrival with a distinctive whistle, a signal that he has come to collect his opponent's Numbers along with their soul. He duels with an icy intensity and shows no mercy to those he believes are responsible for his brother's suffering, viewing his actions not as a choice but as a necessary duty. Despite this cold exterior, his core personality is that of a deeply kind and protective individual, but this gentleness is reserved almost exclusively for Hart, for whom he is willing to sacrifice everything, including his own health. The Photon Transformation, which changes his black coat to white during a duel, grants him immense power but physically and mentally drains him, a cost he readily ignores for the sake of his mission.

Kite’s motivations evolve significantly upon discovering that his father’s claims were a lie. The hunt for the Numbers was part of a larger, more sinister plot, and the people he defeated were innocent victims. This revelation forces Kite to confront the weight of his actions and feel profound guilt for the souls he has stolen. Once Hart is cured and the truth is revealed, Kite abandons his role as a hunter and becomes a genuine ally to the protagonist, Yuma Tsukumo, and his ethereal partner, Astral. His rivalry with Yuma, built on conflicting goals, transforms into a mutual respect and a powerful friendship as they unite to face greater threats. His key relationships also include his fraught, distrustful dynamic with the manipulative Mr. Heartland and his complex feelings towards his father, whom he eventually confronts and reconciles with.

In battle, Kite is renowned for his signature card, Galaxy-Eyes Photon Dragon. His strategy revolves around a Photon and Galaxy-themed deck, focusing on swarming the field with powerful LIGHT-attribute monsters to quickly summon his ace. The dragon possesses the unique ability to banish itself and an attacking monster from the duel, returning at the end of the battle phase with increased strength. Beyond his dueling skills, Kite possesses special abilities. He can read the ancient language of the Number cards, a skill shared by only a few. His Photon Hand is a technological device given by Dr. Faker that steals souls, and he also wields a Duel Anchor to trap opponents, preventing them from fleeing. Later, he receives some of Hart's unique powers, which enables him to see the normally invisible Astral and summon an even more powerful form of his dragon, Neo Galaxy-Eyes Photon Dragon. This power comes at a great personal cost, and Kite continues to fight with it, seeking redemption for his past as a hunter.