In Soul Eater, Asura is the first Kishin and the primary villain of the series. He was driven mad by his fears and seeks ultimate power in order to escape them.
Death created Asura from a fragment of his soul containing his fears about 800 years before the setting of the series. He is thus Death's first son and Death the Kid's older brother. Asura's path to insanity led him to consume the soul of his Magic Weapon partner, Vajra. This enabled Asura to consume pure souls. After consuming 99 pure souls, he consumed a witch's soul and became the Soul Eater world's first Kishin, the most powerful evil being in existence. However, he was defeated and sealed by Death under the Death Weapon Meister Academy until he was awakened and freed during the events of the series.