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Cassandra is the tritagonist of the Tangled franchise. She is the deuteragonist of Tangled: Before Ever After and the tritagonist its follow-up series.
She was Rapunzel's handmaiden and best friend, but at the end of the series' second season, she becomes the central antagonist/deuteragonist and a very great threat to Corona after being corrupted by the Moon Stone before redeeming herself in the series' third and final season.
Cassandra is the biological daughter of Mother Gothel who treated her like a servant than showing any love towards her.
When Gothel kidnapped Rapunzel (who was a newborn at the time) so she can have the princess's magic hair to herself, Cassandra was abandoned by her mother, leading her to be found and adopted by Corona's Captain of the Guards where she would suppress her memories of Gothel as Cassandra grew up.
She is a skilled fighter who dreams of joining the royal guard, though she currently and contently serves as Rapunzel's lady-in-waiting and closest confidante, alongside the princess' pet chameleon, Pascal. Her role generally requires that she assist Rapunzel in any means necessary. She also played an instrumental role in the return of Rapunzel's 70-feet of magic, golden hair.
Cassandra is described as being "tough-as-nails", a fitting description for someone who wishes to join the royal guard. She is snarky, sarcastic and has a somewhat dry sense of humor. Despite this, she is extremely supportive and protective toward Rapunzel, her polar opposite—so much so, that she openly holds animosity for Eugene, believing him to be selfish and undeserving of Rapunzel's love and friendship. One of the reasons for this belief is because she feels that Eugene puts his own desires before Rapunzel's, which she expresses to Eugene.
Although loyal to King Frederic and Queen Arianna, Cassandra is willing to break their rules (and risk her job) for the sake of Rapunzel's happiness; this is seen when Cassandra offered to take Rapunzel beyond the kingdom's wall to explore some of the outside world and escape the pressures of royalty. Doing so required much stealth and cunning, traits Cassandra revealed herself to have that night.
Aside from her no-nonsense personality, Cassandra is also a free-spirit, not unlike Rapunzel. Though she has a more cynical way of going about life, Cassandra also finds joy in adventure, living life to the fullest, and experiencing new things. This is most notably seen during "Wind in My Hair", where Cassandra is seen enjoying herself almost as much as Rapunzel.
In "Challenge of the Brave", it is revealed that Cassandra has insecurities about how she is seen just as a girl/handmaiden instead of a strong, skilled, and capable warrior who deserves as much respect as anyone in the royal guard, this would later contribute to her fall to villainy. These things can at times cause her to act selfishly and make her unable to be able to ask for help sometimes.
Cassandra also holds a strong belief that strangers can't be trusted, like for example when the group first meat Adira she immediately didn't trust her and still didn't even when she proved herself and saved her life and even after she revealed everything to them.
She also shares a strong rivalry with Eugene due to his past as a thief tying into her trust issues but over the course of the series, she becomes a lot nicer to him as well, at least for a while.
Through Season 2 her insecurities and feeling of constantly feeling outshined by Rapunzel cause their relationship to become strained. This only got worse when she discovered her true backstory in the House of Yesterday's Tomorrow and that Gothel choose Rapunzel over her making her steal the moonstone and become a full-fledged villain.
Despite all of this, Cassandra is still shown to have some good in her as she repeatedly reconsiders her path but is constantly turned back to darkness by the Enchanted Girl. This is especially shown in the episode "Be Very Afraid" where it established the only reason the red rocks form is due to her fear of the idea of destroying Rapunzel, as they are connected to her emotions.
In "Plus Est en Vous", Cassandra initially seems to have abandoned all good in her, except for sparing Rapunzel's vase made by her aunt Willow. She also lost trust in Zhan Tiri presumably blaming her for her turning evil. Cassandra gets super close to killing Rapunzel and taking the Sundrop for herself. But then Zhan Tiri betrays her and takes the Moonstone and Sundrop from her and Rapunzel. This causes Cassandra to break down cry and finally apologize to Rapunzel. But when Rapunzel tells her that there is more in her this instills new confidence in Cassandra which has her team up with Rapunzel and finally defeat Zhan Tiri leading to her redemption.
Powers and Abilities
Sewing: When Cassandra was Rapunzel handmaiden, she was able to sew Rapunzel's clothes extremely well.
Fighting skills: Cassandra is a skilled swordswoman and fighter, having trained in the ways of the Corona Royal Guard since she was six years old. For example:
Swordsmanship: Cassandra is shown to be extremely good with swords. As she has a whole collection of them and always has one on her back. She has also stood up to many people in sword combat.
Archery: During "Challenge of the Brave", she uses a bow during one of her challenges and is extremely good at using it.
Martial arts: During some of Cassandra's fights, she pulls out some martial arts.
Acting Skills: Cassandra is shown to have decent acting skills as she uses it to trick Andrew into believing she loved him and that she hadn't caught on to his plans.
She is adept with many types of weapons, as shown through her collection of them in Before Ever After. For example:
Swords: She has a giant collection of swords and always carries one around.
Shadow Blade: When Cassandra and Adira were fighting, she grabs Adria's shadow blade taking it for herself. It is later broken my Rapunzel in the final episode.
Mind-Trap: She steals the mind-trap from the spire which she uses to control the entire brotherhood. It later ends up destroyed by King Edmund.
Shapeshifting Cloak: When Cassandra stole the Shapeshifting Cloak, she could use it to shapeshift into anyone. like for example; The Keeper and Faith.
More Skilled Fighters: While an extremely good fighter she is not unbeatable, as she is overwhelmed by warriors who have trained longer than she herself has been alive, like Adira and King Edmund of the Dark Kingdom.
Insecurity and Jealousy: It was her biggest weakness. The biggest example is that her insecurity and jealousy led to her letting rage cloud her mind and prevented her from seeing what she really needed, something which Zhan Tiri would later use to her advantage. Because of this, it caused her to betray Rapunzel in which she was betrayed by Zhan Tiri as she finished using her in the series finale.