Hisagomaru

瓠丸

Hisagomaru is the manifested spirit of Hanatarō Yamada's Zanpakutō, appearing during the anime-exclusive Toujuu Campaign.
He resembles a simple toy robot, standing about as tall as a three-year-old child. Hisagomaru has a cylindrical body with two arms and two legs, ending in flat plates for hands and feet. His head is perfectly round, featuring one normal eye and another replaced by a gauge that fills as he heals people, similar to the one on his sword form. His chest can open to reveal an enormous cannon.
Much like his partner, Hisagomaru is very timid and insecure. Unlike other Zanpakutō spirits manifested by Muramasa, he holds no personal desires or grievances against Hanatarō. In fact, when Muramasa forced him to materialize, he continually attempted to return to his sword form, falling into great despair (and hiding) after believing Hanatarō had abandoned him.