Life After Life: The Saturn Kheperu Saga

While on a trip to Paris as part of one of Michiru's concert tours, the Outers encounter an evil cult worshipping a malignant entity known as Tsathoggua. During their first encounter with the cult, Hotaru's memories from her previous lives begin to awaken, and the four are saved by a mysterious masked warrior connected to both Hotaru and Tsathoggua. Part of the Old Gods Saga.