A-ou (Japanese/Sanskrit, , one of the two Buddhist Deva Kings) - GOTT ES Member (S Class), apparent age 19, partner to Un-ou. Special ability: "Amplifier".
The older and more stoic member of the Duo, A-ou (unlike his partner) has a stronger sense of honor and justice. He is also more of a pacifist and he often speaks in a profound and meaningful manner, giving him a rather preachy presence among other people. He and Un-ou have had a long and eventful past together during their days as mercenaries. However, despite their differences, the two have forged a strong bond as a team. "Amplifier" gives him the ability to improve his visual perception tenfold. He also uses the energy seen by Un-ou to increase the power of his physical attacks.