Meister Kaio, known in the original Japanese as North Kaio, is a deity who serves as the ruler of the North Galaxy and one of the most important mentors in the story. He resides on a tiny planet, only about one hundred feet in diameter, which is located at the end of a tremendously long, winding road in the afterlife called Snake Way. Despite its small size, his planet has gravity ten times stronger than that of Earth. Meister Kaio has a distinctive appearance, with blue skin, antennae on his head, and small teashade sunglasses that he always wears, meaning his eyes are never seen. He dresses in a traditional Chinese-style outfit. He shares his small world with two animal companions: a monkey named Bubbles and a motor-mouth grasshopper named Gregory.

In terms of personality, Meister Kaio is known for having a very strong sense of humor, although his jokes are consistently terrible and corny. He believes that humor is an essential quality for any warrior, and as a result, he imposes a unique test on all prospective students: they must make him laugh before he agrees to train them. He is also an enthusiast of luxury cars and takes great pride in his red 1955 Chevrolet Bel Air hardtop, which he enjoys driving in straight lines on his minuscule planet. Despite his jovial and sometimes silly demeanor, he possesses great wisdom and extensive knowledge about the universe and its many powerful beings. His motivations are rooted in his duty as a guardian deity, as he seeks to protect the North Galaxy by preparing powerful warriors to face major threats.

Meister Kaio's primary role in the story is as a teacher and an advisor. He is first sought out by the hero Goku, who comes to his planet to train for the upcoming battle against the Saiyans. Under Meister Kaio's tutelage, Goku endures harsh conditioning in the planet's increased gravity, which greatly enhances his speed and combat skills. More importantly, Meister Kaio teaches Goku two legendary and incredibly powerful techniques: the Kaio-ken, which allows the user to multiply their own power, speed, and reflexes for a brief moment, and the Spirit Bomb, an attack that gathers energy from all living things around the user to form a massive sphere of destructive force. Meister Kaio himself admits he could never fully master either of these techniques, making Goku's success with them all the more remarkable. Later in the story, after many of Goku's allies are killed in battle, Meister Kaio also agrees to train them, including Piccolo, Tenshinhan, Yamcha, and Chaozu, helping them reach new levels of strength in the afterlife.

Key relationships define much of Meister Kaio's involvement in the plot. His most significant relationship is with Goku, whom he views as an exceptional student and friend. He maintains a telepathic link with Goku and the other Z-Fighters, allowing him to provide crucial advice, relay information about enemy movements, and even help coordinate strategies across vast interstellar distances. He also has a fierce rivalry with the West Kaio, which reaches its peak during a martial arts tournament in the afterlife. His relationship with his pets, Bubbles and Gregory, is that of a keeper who is often mildly exasperated by their antics.

Throughout the series, Meister Kaio's character remains largely consistent, though his role evolves from a direct trainer to a distant but invaluable strategic advisor. One notable event in his development is his death, which occurs when Goku teleports a self-destructing Cell to his planet in a desperate attempt to save Earth. The explosion destroys the planet, killing Meister Kaio, Bubbles, Gregory, and Goku himself. However, since Meister Kaio already resides in the afterlife, this event does not significantly impact his ability to continue his duties, though he is extremely upset with Goku for sacrificing his planet. Later, he plays a crucial role in the battle against Kid Buu, using his telepathic abilities to allow Vegeta to speak to the entire Earth and convince its people to contribute their energy to a final Spirit Bomb.

Meister Kaio possesses several notable abilities that extend beyond his combat techniques. His most distinctive power is his universal telepathy, which enables him to communicate mentally with any person anywhere in the universe, a skill he can also extend to others. He has demonstrated the ability to use telekinesis and magic materialization, which he uses to create objects like new clothes for his students. He is also an expert in various forms of ki manipulation, including flight and energy waves. However, his true strength lies not in his own combat power, which has been stated to be considerably lower than the major villains and even some heroes, but in his profound wisdom, his status as a source of universal knowledge, and his unique and invaluable techniques that he passes on to his students.