Granpa Kazami is a tanned-skinned, brown-eyed, grayish white-haired and bearded old man. He wears a traditional Japanese dark green kimono and white hakama. His hair is tied in a high pigtail. Additionally, he wears a pince-nez. He is seen with a Bokken, which is his weapon of choice.
Grandpa Kazami is very grumpy and fussy. He is persistent and insists on Shun becoming a ninja champion like he was. He is also very stubborn and sometimes unreasonable, shown when the Battle Brawlers struggled to convince him to get Shun to help them join the fight against Naga.
He has, though rarely, shown a more compassionate side to him, such as when he forced Shun to show him around town and spent time with his grandson. It is in this same episode, that he is shown to also have a sense of humor, saying that he felt like an eighty-five year old and Shun teases him by saying he is one.
Another time, he brought Shiori's purse (which Shun was supposed to bring) and stayed with her in her hospital room. He also tells Shiori not to worry about him. Generally, though he rarely shows it, he cares for the well being of his grandson perhaps more than him becoming a ninja champion.
His mansion resembles a large dojo and has many traps installed inside. He wants Shun to be a ninja, as he was once a greatly skilled ninja. Shun came to live with him after his mother had to stay at the hospital after being ill. He is very fussy at times. Shun does go out with him in regular times though, as seen where he shows his grandfather through the city. In the English dub, he is stated to be 85 years old. Julie mistook him for Hal-G.
- He is most likely Shun's paternal grandfather because:
- Shun's mother has a pale complexion while Grandpa Kazami has a dark complexion. Shun has a fairer complexion, which he may have inherited from his mother.
- Shun's mother has green eyes while Grandpa Kazami has brown eyes, just like Shun.
- When Shiori Kazami fell comatose in the hospital, Grandpa Kazami did not show the same concern as a father would be for his daughter.
- Shun's mother does not seem to know anything about ninjutsu, just that its not what Shun wants.
- Shun's mother does not bear a single resemblance to him.
- When Dan found out from Runo and Marucho that they had tried and failed to recruit Shun; he went back to Shun's grandfather's house with them. When Dan got there, he did not once get caught or trapped by any of the booby traps set by Shun's grandfather unlike Runo and Marucho. Considering that Dan knows Shun from childhood, it is possible that Dan had been there a couple of times before and knew where the traps were set and over the time, had learned to evade them.
- Grandpa Kazami has met all of the original Battle Brawlers in person.