Callisto is a vengeful warrior from Xena's dark past. She is Xena's arch-enemy.
Callisto came from the village of Cirra in ancient Greece. As a young girl she witnessed her village and family be destroyed by Xena in her evil days. This event twisted her into an evil, destructive warrior bent on revenge against Xena. She is one of Xena's biggest and most persistent enemies.
Callisto is a bitter and twisted individual. Her vengeful ways drive her to delight in the torment of others. She would murder anyone to further her own plans. Although she doesn't hesitate to welcome her own death, if the opportunity arises, to end the pain she suffers from losing her family. Even though she wants revenge she ultimately wants to end her own suffering but not by her own hand.
Like Xena, she also dresses in leather armour and is armed with a sword sheathed on her back. She is very proficient in combat and is almost Xena's equal.