Kaito Tatsuno is a teenager whose father helped design the Dinoterium, a facility for dinosaurs, though Kaito himself initially had little interest in them. Witnessing Dragozaurs stealing local life force changed his life; his impassioned cry for life accidentally reawakened the dormant Dino Knights, forging an immediate alliance. He wields one of three Dino Daggers, artifacts that restore a Dino Knight's strength and power them up with the command "Dino Power, Energize!".

He has brown hair and typically wears a red and yellow tank top over a white shirt, blue calf-length jeans with a large pocket, and red sneakers. Kind towards all animals, Kaito shows deep concern for the Dino Knights' well-being, often worrying when they face danger. He shares the secret of their existence with Rena, a friend since kindergarten who possesses another Dino Dagger.

Throughout the conflict, Kaito actively supports the Dino Knights against the Dragozaurs. He travels to locations like Africa to assist Dino Sabre and Dino Tricera in investigating Dragozaur activity near water springs, and journeys to New Mexico to help locate and awaken the Cerazaur Brothers: Dino Centro, Dino Toro, and Dino Styraco. He also participates in missions to volcanic islands to identify and protect the Dino Weapons, who transform into armaments for the Dino Knights.

His involvement escalates during critical events, such as seeking the legendary phoenix-like Dino Rhamph in Central America to recharge Dino Tyranno during a battle against Gigano Dragon. In the climactic confrontation in Antarctica, he works alongside Rena and Rick to awaken Dino Rhamph and counteract Diamond Ryugu's efforts to drain Earth's life force. Kaito evolves from a bystander into a committed participant defending the planet.