Xena's story is one of pain, heartache, betrayal, and, ultimately, redemption. Her first appearance in Hercules: The Legendary Journeys showed a woman who was willing to do anything in order to get her way, while the first episode of her solo series gave viewers someone who had changed drastically due to her encounters with Hercules and Iolaus, who now seeks forgiveness for the sins of her past. Originally cunning and happy to use her charms in service of evil, the titular Warrior Princess starts off her own show tired, shamed, and striving toward a better life.
Yet forgiveness is a many-faceted jewel, and Xena's crimes included looting and murder. These things had real-world effects that could never be erased. In the first season, we met Callisto, the embodiment of all the malice of Xena's transgressions — a girl reeling from the trauma of losing her family to Xena's army who then went on to become a warrior of equal caliber simply to ensure that Xena would never be able to forget her mistakes. It is because Callisto's rage is fully justified that she is so frightening, and it is that key element that made her one of the greatest villains not just of the show itself, but in genre, period.
Welcome To The Club
In the beginning, Callisto was just a young girl living in the town of Cirra. Not much is known about her life there, but we do know that when Xena's army took the town, her father, mother, and sister were all casualties of the invasion. Years later, Gabrielle attempts to reach out in understanding by asking why Callisto does the things she does. Callisto explains that she no longer feels anything at all, urging Gabrielle to "think back to when you were a little girl and all you knew was your mother and your sister, and all of your faith revolved around them. Now ... kill 'em."
The fact that Xena's crimes completely ruined Callisto's life is unquestionable, and in the background, Callisto forges herself into the same brutal killer that Xena once was. Though they both had similar origins, their families destroyed by warlords, they also each became vengeful monsters in their own time. When Xena attempts to break this cycle, Callisto is always there trying to pull her back in.
Here Comes Trouble
Callisto's first appearance on Xena: Warrior Princess fills us in on who she is and where she comes from, and though Xena attempts to apologize and reason with her, Callisto responds with nothing but anger. The people that Callisto has hurt demand her head, and Xena tries to protect her, to which Callisto replies, "You let me go, and I will dedicate my life to killing everything you've loved — your friends, your family, your reputation, even your horse. You see, I am being so honest with you because the idea of your pity is worse than death for me. ... You created a monster with integrity, Xena. Scary, isn't it?"
Xena struggles with guilt and remorse over her actions, and there are no easy answers to the moral quandary Callisto poses. If Xena frees Callisto, she will continue to kill. If she kills Callisto, then it reflects the failure of her own redemption. She ultimately attempts to imprison the other warrior, but Callisto breaks free and maliciously kills Gabrielle's husband. When Callisto falls into quicksand, Xena pulls back her hand and refuses to save her, but even in the underworld, Callisto and her embodiment of Xena's crimes still exist. Thanks to a deal with Ares, she even takes over Xena's body for a time, and although Xena does win her way out of that predicament as well, it's obvious that Callisto's commitment to destroying everything the other woman loves has not waned and never will, even in death.
At first, Callisto makes it clear that she'd do anything to escape Tartarus, and even makes a deal with Hera to fight Hercules. This ends with her nearly achieving redemption, but Hercules returns to fight her without fully understanding her change of heart and thus brings her back into her prior state of rage. At one point, Xena also bargains with Callisto to help her fight the embittered Amazon-turned-immortal Velasca, cutting the ropes on them both when they lure each other into a fight on a bridge over lava. Of course, this is yet still not the end of Callisto, and she returns in alliance with Gabrielle's demonic child, Hope.
When Callisto gains both immortality and the power to kill gods and is reluctantly admitted into the Greek Pantheon, she mutters, "I wouldn't be a part of any club that would have me as a member," and stabs the minor god Strife to death. She used her newfound powers to travel into the past in hopes of preventing her family's death, but by then her anger had become its own self-fulfilling prophecy. In attempting to save them, she kills them herself and leaves her devastated younger self reeling in the war-torn village just as Xena had once. After this, Callisto becomes fully despondent and wishes only for her own existence to end. Xena grants her wish by killing her, but Callisto will always return.
The New World Can Be Built On The Foundation Of The Old One
Things get even more complicated after Callisto helps cause Xena and Gabrielle's death during the episode "Ides of March." In the afterlife, Xena confronts a demonic Callisto, and the two fight. Ultimately, Xena sacrifices her own divinity to grant it to Callisto, who appears as an angel, devoid of the hatred that marked so much of her life. Later, when Xena has a mysterious pregnancy, we discover that Callisto had impregnated Xena with her own spirit in a way to give her something after they had taken so much from one another. It's a strange ending to a strange tale, but suffice it to say, even Xena's daughter, conjured to life through divine means, suffers from the cycle of violence that began so many years before.
In a series that is so defined by a quest for redemption, Callisto is an important counterargument that forgiveness is a lot more complicated and takes a lot more time than we want it to. While many characters struggle with metaphorical demons, Callisto was tangible, real-life proof of all the harm Xena had done in her life. In her many appearances on Xena: Warrior Princess, Callisto taught our heroes a lot of lessons. For Gabrielle, the lesson was that some people don't want to be redeemed, but sometimes when you forgive, you do it not for those who have hurt you but for yourself. For Xena, it was that some things truly can't be forgiven, but it doesn't mean you stop trying to do the right thing going forward.
Still, in the end, the most painful lessons on the series were learned by Callisto herself — when she was forced to see that, beyond what Xena did to her, she was fully and completely responsible for her own actions in life, and the blood she shed was on her hands and hers alone.