Blood Knight: Although she has always enjoyed battle and thrives in the midst of it, after Caesar screwed her over, she became this in a very bad - and indiscriminate - way. Even after her Heel-Face Turn in Hercules, she still contains elements of this.
Rousseau Was Right: Though once a brutal warlord, she only raised an army in the first place to protect her home village from raiders. The death of her brother and then Caesar's betrayal helped push her over the edge.
Shamu Fu: Many times. Including that one when the defeated a whole army with it...
The Strategist: she is an honestly brilliant military commander and strategist. There is a very good reason why she got the title "Destroyer Of Nations" and why in just ten years she became one of the most formidable warlords of all time.
Badass Bookworm: Gabrielle is a bard by profession, always writing stories. As the series progresses, she goes from innocent non-combatant to a highly skilled fighter in her own right who earns the Fan Nickname "The Battling Bard of Potidaea".
Nice Job Breaking It, Hero: Gabrielle does this once per episode early on. Of course, her biggest example in this regard is letting Hope live and lying to Xena about killing her. Lots of consequences there.
Thou Shall Not Kill: Not until the end of season 4 that she learned she always can't stick to this rule. And then she just threw the rule away altogether and started killing people left and right. (There's not really a good justification for this other than that she found pacifism too hard.)
The Unfavorite: Implied to be this in his family, since his father was a warlord and his brother is a skilled assassin, while Joxer himself isn't much of a warrior. Even his Camp Gay other brother who works as a singer got more respect.
Vitriolic Best Buds: With Autolycus, though the insults largely only come from the King of Thieves.
Everyone Has Standards: Never steals from anyone that can't afford to lose it. He once demanded that a poor community pay a large amount for his services, but then he secretly gave it back to them when the mission was done.
Freudian Excuse: In his first appearance, he explains to Hercules why he's a thief.
"A bloated merchant from Cyros tricked my brother, Malachis, out of his land. And when Malachis protested, the merchant had him killed. And the-powers-that-be did nothing about it. So, I delivered my own justice. I robbed that merchant, and I gave every dinar he had to the sick, the hungry, the poor. The merchant became a pauper. And, well, I became an outlaw... but not just any outlaw, either."
A runaway slave from Gaul who ends up on Xena's pirate ship at the same time as Julius Caesar. She becomes the first of several of Xena's mentors.
Foreshadowing: The little girl at the beginning of "Destiny" has a necklace like M'Lila's, and appears to speak the same language as M'Lila.
Mentor Occupational Hazard: Although she isn't older than Xena, she is still the first of several characters from Xena's past who helped shape the Warrior Princess we know today, and her death at the hands of Roman soldiers sent to apprehend them is the final straw that sets Xena on the path of darkness.
Xena: “You’ll be dead in thirty seconds. But know this - you won’t be the last. Tell Hades to prepare himself. A new Xena is born tonight - with a new purpose in life - death.”
Redemption Equals Death: He is remembered as a hero by every Centaur on earth after allying with them against Xena.
Lao Ma (Jacqueline Kim)
One of Xena's mentors, and the first person to attempt to turn her back to good during her warlord days. She is the wife of Laozi and according to the Xenaverse, she is the real author of the Daodejing.
Hell-Bent for Leather: She tries to pull it off, but can't quite match Xena for Fanservice. Not that her boyfriend Hower was complaining once he saw Minya in her leather.
Hide Your Lesbians: Possibly. She says at the end of "The Play's The Thing" that she's a "thespian," but it's a bit hard to hear, and she might be saying something else entirely. It certainly sounds like a confession of a different sort, especially as she says fellow female cast member Pollina helped her to come to this realization.
Minya: "The two of you made me realise something deep down inside myself that I guess I always knew but I didn’t dare admit. I’m a thespian."
Xena's daughter chosen to be the new messenger of the god of Love. Her birth heralded the Twilight of the Olympians so Xena faked her and Eve's death. Eve, as Livia, was raised by Octavius to become Rome's most powerful warrior.
Love Redeems: He has been in love with Xena for a long time, but instead of confessing to her, he's so terrified of rejection that he constantly invents stupid plans to try to force her to be with him. Considering that he was born to be a war god and that that is his innate nature, it is understandable that this would be the way he would try to court her, but this is possibly the worst way to approach Xena. Nevertheless, he does in the end sacrifice his godhood and his own future for her.
Former Xena victim now bent on her destruction. Becomes an angel in season 5 thanks to Xena.
And I Must Scream: After she dies the first time, Callisto's existence boils down to this. She is so consumed with hate for Xena killing her family that she can't find peace even in death. (In the HTLJ "Surprise" episode, her version of Tartarus is simply her alone and screaming in agony.) It gets worse when she realizes there is nothing she can do to Xena to make her feel the same way.
Annoying Arrows: Provides the picture for this trope, from "Maternal Instincts".
Psycho for Hire: often enemies of Hercules or Xena will try to use her to their ends, and she goes along with it in the hope that causing Xena the same crushing agony that she experiences will stop it.
Pyro Maniac: she has a horrible obsession with fire. A very unhealthy one.
Reformed, but Rejected: the look on Callisto's face after Xena has given her Light and Gabrielle tells her about her horrific crimes is, in itself a Break the Cutie moment. She looks absolutely heartbroken.
Trauma Conga Line: she went through Break the Cutie as a little girl and then the hits just kept on coming, with the hate, anger, and pain building to insane heights. She's a rather odd example in that all her attempts to stop the pain amount to her trying to harm others, and so she unintentionally instigates the events that cause her more pain. She does in fact get Driven to Madness by the sheer agony and her emotional spectrum is so fractured that often she can't feel anything at all.
With Cyane, Queen of the Amazons. Cyane bests her in a mental showdown, though Xena ultimately sides with Alti, and kills Cyane and the other Amazon leaders.
Cyane: Your choices are simple, Xena. Side with us and find life, or side with Alti and find death.
Alti is also an opposed mentor to Lao Ma, though Xena only meets her after she leaves Lao Ma.
Alti: Your friend you told me about, Lao Ma, her powers come from denial, from self-sacrifice, from the light. That’s not for people like you and me. I wanna tap into the heart of darkness - the sheer, naked will behind all craving, hatred, and violence. I’ll become the face of death itself - capable of destroying not only a person’s body, but their soul. Help me, and I’ll make you ‘Destroyer of Nations’.
Past Life Memories: She uses memories of this life in her next life to fight Xena and Gabrielle in their next lives.
Woobie, Destroyer of Worlds: Several people try to kill her before she's even born and continue even afterward. Even her mother, Gabby, abandons and then attempts to kill her. Despite this, Hope is willing to forgive her mother and wants to be close with her. Gabby's not interested. To be fair, the reason why this is, is because not only did Hope kill someone in cold blood within an hour of being born, all that she is interested in is to kill and torture people. Yes, she wants Gabby to be close with her... so they can both take over the world and kill everyone within it. Her intrinsic nature is geared towards murder and torture, even though she knows that it is wrong and that not only would Gabrielle disapprove of her actions but that they cause great pain and suffering (she lied and manipulated Gabrielle of her own volition when she killed Solan and tried to pretend she was innocent). However, HER child could be considered the real Woobie, Destroyer of Worlds.