The Rabbit Hatch was once part of an OSTO complex that was destroyed seventeen years before the start of the series. Kengo then found the base through the guidance of a man who knew his father after finding a secret locker and used it as his base of operations. After serving the Kamen Rider Club for all this time, and being used by the heir of Rokuro Utahoshi, the Rabbit Hutch is ultimately destroyed as the Sagittarius and Leo Horoscopes laid waste to the facility to kill Kengo, and ultimately succeeded.