Description

My Younger Sister is My Roommate! begins when a broken water pipe at Yui’s dormitory leaves her needing somewhere to stay while repairs are underway. Her temporary solution is her older brother’s home, bringing the siblings together again after years apart. The reunion is hardly a warm one: Yui treats her brother coldly, yet she is also completely unreserved around him. That contrast sets the tone for a story centered on an unexpected living arrangement, as a long-absent younger sister suddenly becomes a roommate. Developed by OMNC and originally titled 妹はルームメイト！, the game was released on October 26, 2026, and is available through DLsite. Version 1.0 runs on Windows and supports English, Japanese, and Simplified Chinese. The release includes mosaic censorship.