Zanbai was a bald man and light eyes, with many scars across his head and face. He wears a typical black kimono with a white sash.
Zanbai attends a meeting of the Council of Swordmasters. At the meeting Kamikaze asks the council members for help in catching and killing Garou in worries that Bang might fail and die. The council members agree, except Haragiri who mocks Atomic Samurai's plea. Haragiri proceeds to show them the Monster Cells and reveals he had received them from the Monster Association and transforms into a Mysterious Being himself. He then orders the council members to eat the cells or he will kill them, but Atomic Samurai cuts him first, killing him.
Later, Zanbai along with Nichirin, Amahare, and Spring Mustachio come to the heroes support against the Monster Association. Upon arriving, he assists the other heroes and fights Black Sperm alongside them. While Zanbai is defending against countless copies of Black Sperm alongside his comrades, Fuhrer Ugly arrives in his mutated form with Gums' stomach acid covering the former's entire body. After a brief clash between Superalloy Darkshine and Fuhrer Ugly, and seeing the former severely harmed by the super-powerful acid covering the monster's body, Zanbai advises everyone not to face the fat monster empty-handed and then charges at him with a sword. However; Fuhrer Ugly manages to catch his sword, instantly melting the sword due to the acid covering his hand, and then retaliates against him by shooting an acid spit from his mouth on to Zanbai's head. He is then killed by the powerful acid from the monster as it melts through his head.
Abilities and Powers
Being a member of the Council of Swordmasters, Zanbai was presumably a very powerful swordmaster. Atomic Samurai was confident enough in Zanbai's strength to ask him to assist the hero in pursuing and facing Garou rather than relying on the Hero Association. Alongside the other heroes and the other members of the Council of Swordmasters, Zanbai was capable of fending off countless copies of Black Sperm surrounding him during their fight.
Enhanced Speed and Reflexes: Zanbai possessed a decent amount of speed and reflexes. He was capable of drawing his sword and slashing at high speeds and holding his own against many clones of Black Sperm surrounding him.
Master Swordsman: As a member of the Council of Swordmasters, Zanbai is a highly skilled swordsman. He was able to skillfully decimate mutiple clones of Black Sperm using his sword.
- Peaceful Death (大往生, Daiōjō):
Katana: Zanbai carried a katana on his person.
- Zanbai's face appears to be modeled after Ken Watanabe, a Japanese actor known for playing samurai characters in productions such as Mibu no Koiuta and Dokuganryu Masamune and Last Samurai.