Kurako is a mechanical doll under Sakurako Sakurakouji's control.
She is a doll, like Inoichi, and also physically strong and fast. She able to "heal" the Emperor by kissing Ogami, which embarrasses Sakura a lot. She also has feelings towards the Emperor.
The ironic thing is her name, Kurako, literally means gloomy girl. Unlike Inochi, Kurako seems more emotional, crying easily at trivial things.
Her only desire or purpose was to revive Code:Emperor. She helped to bring out the good side of Code:Emperor at first, but Ogami refused, saying that he is more comfortable with old emperor. Happy with Ogami's choice, she kissed him, shocking Sakura and Ogami. That kiss actually gave Ogami energy and brought Code:Emperor back. After she finished her purpose, she collapsed and stopped functioning.
It was also revealed that the puppeteer and creator of the dolls is actually Sakura's real mother.