12,000 years prior to the beginning of the game story, Asura had a somewhat happy life with his wife Durga and his child, Mithra. He and Yasha were students of Augus and they participated in numerous battles against the impure Gohma. At some point in the Emperor's castle, Sergei, Wyzen and Kalrow confronted Asura and Wyzen tried to persuade him to join Deus's cause, The Great Rebirth, but he declined. Later when his daughter was appointed new priestess, he was outraged and didn't want his daughter to be involved in war. After the battle against the Gohma and Vlitra he was framed for killing Emperor Strada by the Seven Deities and stripped of his godly powers and plunged into Naraka. His daughter kidnapped, his wife killed, Asura is now on a quest of vengeance fueled by pure rage.
(Source: Asura's Wrath Wikia)