Mana for Android (Sakura Kizuna) developed by Polar Bone, a character development company. Once completed, it is planned to be mass-produced and named "Mana Plan". Takuma, who created the character design and participated as an observer in this three-dimensionalization plan, was using this prototype as a cohabitation partner. Meanwhile, heroine Mana's rival character Jun (Mary Tachibana) was also one of those born from the previous plan, like Mana.