Donten ni Warau Gaiden: Ouka, Tenbou no Kakehashi [Sub: Eng]

The three brothers discover that the human experiment banned after destroying the 'Orochi', is still going on to secretly revive the evil snake. They also find out that some ex-members of the Yamainu (the Japanese military unit formed to kill the snake) are behind this conspiracy. The brothers fight together again in a battle against the military.