Kaito Unabara is one of the main protagonists of the Beyblade: Shogun Steel series, serving as a rival and later an ally to the main character, Zyro Kurogane. He is the older brother of Eight Unabara and carries a self-proclaimed title of Beyblade researcher. A tall and slightly muscular teenager with olive skin, Kaito has spiky brown hair, thin eyebrows, and deep blue eyes that are usually framed by a pair of glasses. His attire consists of a white lab coat with blue and yellow lines over a green-collared shirt and a red necktie, which he wears with tight navy-blue pants and dress shoes. This outfit reflects his analytical and methodical approach to the game.

On the surface, Kaito is a fierce, confident, and highly intelligent blader who prides himself on his extensive research. He uses a portable computer to study the Beyblades of his opponents, analyzing their data to formulate precise strategies that target their weaknesses. His battle style is predominantly defensive, preferring to control the center of the stadium where his Beyblade, Guardian Revizer, can deflect attacks and drain the opponent's spin energy. This calculated confidence, however, often borders on arrogance, as he places absolute faith in his predictions and sometimes believes victory is assured before a battle even begins.

This reliance on logic and data is also Kaito's most significant flaw. When a battle does not proceed according to his calculations and an opponent defies his research, he undergoes a dramatic mental breakdown. In this state, he throws off his glasses, loses his composure, and abandons his defensive strategy entirely. He becomes reckless and aggressive, switching to a relentless offense in a desperate attempt to overpower his opponent. While this shift can be powerful, it is born of frustration and often leaves him vulnerable, as seen in his first battle against Zyro. Once the battle concludes, he quickly returns to his calm and collected self, seemingly with little memory of his violent outbursts.

The most defining relationship in Kaito's life is with his younger brother, Eight. As the older sibling, Kaito is deeply protective of him and is driven to avenge any losses Eight suffers, such as when he challenged Yoshio Iwayama after Eight was defeated. While he cares for his brother, his obsessive research can sometimes cause him to be dismissive and short-tempered, at one point knocking food out of Eight's hands in a fit of frustration over an inability to find data. Despite these moments, their bond is one of mutual support, and Eight is often the one to help bring Kaito back to his senses after a breakdown. Kaito's rivalry with Zyro Kurogane is a catalyst for his growth. Zyro is the first blader to effectively counter his defensive position and survive his reckless offense, forcing Kaito to acknowledge that strength cannot always be quantified by data alone. This respect ultimately leads to Kaito and Eight joining Zyro's group of friends.

As the story progresses, Kaito begins to move beyond his solo, data-driven methods. He becomes a key member of the team, and his primary strength evolves into the use of Synchrom, a technique that allows him to combine Guardian Revizer with Eight's Beyblade, Pirates Orojya, to create the powerful Orojya Revizer. This combination uses the defensive capabilities of Kaito's Bey with the stamina of his brother's, demonstrating his growing ability to rely on cooperation rather than just calculation. He officially enters the Neo Battle Bladers tournament to prove his strength. Throughout his journey, he faces and defeats various opponents, including a blader named Gen and several of Akuya's gang members, while also suffering losses to powerful bladers like Sakyo and Yoshio that force him to continually reevaluate his strategies. Despite his intense and sometimes volatile personality, Kaito is shown to enjoy casual moments, such as swimming with his friends and playfully stealing food, reminding that he is not solely defined by his intense Beyblading persona.