Captain Yamanaka is a rogue military commander in the Captain Harlock series.
Captain Yamanaka is Maji's former commander. While still members of Earth's military, the two encountered Captain Harlock in a space battle and were handily defeated by him. With their lives having been spared, the two slowly begin to admire Harlock and the freedom that his pirate life affords him.
After Maji marries a beautiful woman named Aki, Yamanaka disappears only to reappear years later telling Maji that his wife is actually a Mazone spy. Maji refuses to believe him, but things come to a head when Aki attempts to murder Yamanaka only to be gunned down by him. Yamanaka asks Maji to join him in defeating the Mazone but Maji refuses, still in shock from the revelation of the alien Mazone, the death of his wife at Yamanaka's hands, and the kidnapping of his daughter (Midori) by the Mazone.
Yamanaka leaves and is killed by a Mazone trap some time later.