Ketsu Onyo was a Mandalorian bounty hunter and an old friend of Sabine Wren.They apparently attended the Mandalorian Imperial Academy together until they escaped. They were close friends, considering each other sisters, and had plans to become bounty hunters to join the Black Sun, and for an unknown period of time they worked as freelance bounty hunters. However, at some point, Ketsu abandoned Sabine to save herself, and at eventually succeeded in joining Black Sun.