Black God Vol. 4 (manga)

After overcoming the initial shock of seeing his dead mother in a recent photograph, Keita travels to Okinawa with Kuro and Akane. Following a reunion with his karate-master grandfather, Keita and company are led to an island where they meet twin feral Mototsumitamas. Though they’re initially hostile, it seems the twins hold a piece of the puzzle that will bring Keita and his companions closer to the truth about the aims of the ruthless Shishigami. But as they get closer to that truth, Keita comes face-to-face with his mother!? Or is she…?