I'm a craftsman and I work with bamboo as you can see. But I can't get any to work on right now. Oh, I shouldn't burden you with my problems, wolfy...Mr. Bamboo
Prior to the events in the game, Mr. Bamboo was in Sasa Sanctuary, harvesting bamboo for his bambooware. He discovered an object resembling a metallic bamboo shoot, and Kaguya inside. She looked like she was going to die any minute so he took her back his home to Kusa Village. There, both he and his wife raised her as if she was their own. His wife eventually passed away, and he and Kaguya continued to sell his bambooware. He briefly separated from her when she went to Sei'an City and was imprisoned by the Emperor.
Amaterasu and Issun first meet Mr. Bamboo in Kusa Village, who tells them about his troubles. He can't get any bamboo because Sasa Sanctuary suddenly closed their doors to outsiders due to Chun's disappearance. When Sasa Sanctuary is accessible, he turns up right away when Amaterasu talks to the sparrow outside, who is trying to get hot spring water back because the spring dried up. Mr. Bamboo helps out and introduces the "Digging minigame" to Amaterasu.
He later plays a smaller role when Kaguya wants to return home. He appears only briefly, when talking to Kaguya when she first arrives in Sasa Sanctuary, before she leaves, and as her rocket is flying away. His last appearance is in the scene before the final fight with Yami, where he acknowledges Amaterasu as a god.
Mr. Bamboo has an old, elderly appearance, sporting a bald head albeit with white hair on his sideburns and the back side of his head. He also has white eyebrows, a long chin, and a short height. He wears a green kimono with a small orange vest. The peculiar bamboo tube on his back is known as a sōzu (添水, "water accompaniment") a type of shishi-odoshi (鹿威し, "deer scare"), which humourously reacts to underground sources of water by clapping Mr. Bamboo on his head, acting as a dowsing rod. He also carries around a bamboo cane.
Mr. Bamboo is a kind, elderly person, and he cares for almost everyone he meets, most notably caring deeply for Kaguya, saying that she's his "most precious grandchild", even if there is no relation between him and Kaguya. In the scene when she flies away in her rocket, a tear can be seen falling from his eye. He is, at first, very sad when she's gone. However, he wants to create a "bamboo palace" for Kaguya when she returns, showing that he's optimistic that she'll be back.
- The character and his plot is inspired by the Tale of the Bamboo Cutter of Japanese folklore.