Ceres, Celestial Legend - Double (Vol. 6)
Toya receives a jolt to the head and suddenly remembers everything about his past-a simple life with a girlfriend who is a dead ringer for Aya!  Regaining his memory has somehow caused Toya to forget everything that's happened in the past year.  Including his memory of Aya.  If Aya has a Double, does that mean that there's also another Ceres?