Genbu is a very large tortoise with a snake wrapped around his midsection. He is the 2nd boss encountered by your clan, and has 2600 health. Unlike most tortoises, Genbu is capable of running at fairly high speeds, and can chase Ninjas for short periods of time. Genbu is first encountered in battle at Level 15. During the Genbu's turn, it will choose one of three moves- to charge at a single ninja with a high-powered attack, shoot a massive laser that harms all ninjas, or heal itself. When its health lowers below 1000, Genbu will glow red, greatly increasing its attack and healing power.
After defeating Genbu, the player will be awarded the "Tortoise Slayer" achievement, with a prize of 10 karma. If the player defeats Genbu with only food items equipped (negi, shrimp, pocky stick), the player earns another achievement, "Don't Shoot Lasers With Your Mouth Full", also worth 10 Karma. The found item is not a weapon, as with other bosses, but a relic: Genbu's Scale, which has +10% critical hit chance and +8% attack speed. Upon defeat, the snake of Genbu wraps around the basket of the player's clan's Fight blimp.
Genbu is also encountered in a mini-game, in which the player rescues an ally's ninja. During the rescue mission, the player must run away from Genbu while carrying the incapacitated body of their ally's ninja. At the same time, the play must dodge shurikens being throw from a blimp. With every hit the player takes, he or she will slow down, and, if hit enough, the player will be attacked by Genbu. For every shuriken dodged, Genbu will be wounded, and eventually will give up chasing the player, ending the minigame. The player is graded based on how well they dodged the shurikens.