Koto is a small robot bird who originates from Comet Robo, a planet inhabited by robots. Koto serves as the loyal partner and traveling companion of Roboly, a robot girl who sets out on a journey to discover an important thing that she cannot create on her own. During their travels, Koto and Roboly find a gift box containing a music box, which leads them to the world of Anpanman as they search for its owner. As a robot bird, Koto likely possesses the ability to fly and assists Roboly in her quest. Koto's role in the story is to accompany Roboly, supporting her as she gradually forms bonds with Anpanman and the other inhabitants of his world. Beyond these core details, no further information about Koto's personality, development, or specific abilities is available.