Genres: Action, Conspiracy, Super Power, Tragedy, Violence
After the incidents in Tokyo, Hei and Yin try to bury their past and start a new life, but everywhere they go someone seems to be following them. Unaware to Hei, Yin\'s current odd behavior appears to be related to a prophecy that might lead to the end of the world.
Gaiden fills the gap between Darker Than Black and Ryūsei no Gemini. We are going to find out why Hei was after Yin and what she is exactly.