Cassandra (also known as The Witch of Donan Wood) was an ancient Immortal and witch.
Born during the Bronze Age (at least 3000 years ago), Cassandra was gifted with remarkable healing skills and was quickly adopted and raised by a nomadic healer. She experienced her first death when the Four Horsemen massacred her and her tribe. After resurrecting, she was taken as a sexual slave by Methos, who perverted the teachings of the Immortals into a lie that she would remain alive only as long as her Master chose and said that he would kill her as many times as it took to tame her.
In time, she becomes compliant and obedient to Methos, but when he hands her over to Kronos, she fights back. Eventually, pretending to be broken by pain, she agrees to please Kronos, but instead stabs him with a dagger and escapes into the desert. Methos watches her leave and does not attempt to capture her.
Cassandra spent the next thousand years refining her healing talent into a new skill: the power of hypnosis and suggestion. She was able to pass this teaching on to the Immortal Roland Kantos, a deed she would later come to regret deeply.Sometime before the end of the tenth century, Cassandra became aware of a prophecy: a Highland foundling born on the winter solstice who passes from darkness into light is destined to "challenge the voice of Death." Realizing this would be an Immortal who would be able to defeat her enemy Roland, she travelled to Scotland and built a cottage in the Donan Woods. For centuries she waited, watching the clans, practicing her craft, and building her reputation as the Witch of Donan Woods. She knows of Connor MacLeod (who becomes Immortal in 1536) either through meeting him or from legends the locals told.
On 1 May 1606, thirteen-year-old Duncan MacLeod and his cousin go to hunt a white wolf in Donan Wood. The wolf leaps at Duncan, who blacks out, then awakens on the bed in Cassandra's cottage. He leaves the cottage and sees her bathing in a forest pool. She shelters the boy, explaining herself to him and giving him some hints of his future, and shielding the two of them from Kantos, who had arrived in Glenfinnan in search of him. After the danger is past, she kisses Duncan goodbye and hands him his sword. He looks at her in wonder, saying, "You're the wolf." She simply smiles in response, and he goes to his father, who is nearby. When Duncan looks back, Cassandra and her cottage have disappeared into the mists, leaving no trace of her existence.Cassandra endures the next 390 years in hiding, surviving the Gatherings of 1985 and 1992. After Duncan takes a Dark Quickening in March 1996 and emerges from it, she knows the time of the prophecy is at hand. Enlisting the services of a New York private detective, she tracks MacLeod to his dojo in Seacouver, revealing herself to MacLeod just as the Highlander himself is returning from Paris (6 June 1996).
Hot on her heels comes Roland Kantos, and Cassandra is hard pressed to keep MacLeod alive before he can piece together the riddle of the prophecy that had united them. After MacLeod finally defeats Kantos (8 June 1996), Cassandra departs, the prophecy finally fulfilled - but not before fulfilling a personal desire to take the Highlander as her lover.
Just five months later, Cassandra reenters MacLeod's life when she uncovers information on the whereabouts of her ancient enemy, Kronos. Consumed with revenge, she tracks her adversary to a Seacouver warehouse, only to run straight into Duncan MacLeod, also hunting Kronos under his guise of Melvin Korran. Things go from bad to worse the next morning when Cassandra discovers Methos, her former captor, chatting amiciably with Duncan. Methos says he doesn't recognize her; she (via flashback) relates his crimes and tries to take Methos's head. Methos doesn't draw a sword and Duncan stops her, as he does not believe Methos could have done such horrible things. Methos leaves in a hurry.
Cassandra tells MacLeod that Methos is a liar and that: "He was one of the Horsemen. He killed and raped alongside Kronos"; then she leaves. She tracks Kronos to his hideout in an old power plant and challenges him. The fight goes badly for her, as he is immune to her suggestive voice and her sword skills aren't great, and she's trying to escape when Methos knocks her out and drops her in a river to get her out of the way. Meanwhile, Duncan has arrived and is fighting Kronos. Methos breaks up that fight by starting a fire, then leaves with Kronos. Kronos doesn't trust Methos and is considering taking his head, but Methos says he knows where their two brothers are, and that the Horsemen can ride again.
Duncan returns to his loft and finds Cassandra there. They hug, and she says, "It'll never be over until they're both dead." Duncan replies, "Then we'll find them." With the help of Joe Dawson, a mortal Watcher, Duncan and Cassandra follow Methos and Kronos, who are en route to Europe to locate their lost brothers Silas and Caspian.
In Bordeaux, Duncan gets a phone call from Methos, asking him to meet. Duncan lies to Cassandra, telling her there's a problem with his credit card and that he'll "be right back." While Duncan is gone (disarming a bomb that Methos tells him about), Kronos, Silas, and Caspian go to Cassandra's hotel room. Kronos stabs her with the knife she used on him, all those years ago, and then (quite probably after gang rape) Kronos takes her back to his lair at an abandoned Nazi submarine base, while Caspian and Silas go to kill Duncan.
In the submarine base Cassandra is locked in a cage, and she and Methos talk about old times. She denies ever loving him; he says, "You thought you did" and talks about the Stockholm syndrome. She is defiant and refuses to help him keep Kronos happy, saying, "I didn't do it then, and I won't do it now. I'd rather die." Methos, annoyed, tells her "Then you'll die." As he leaves, he informs her that Duncan is dead.
About a day later, Methos is sitting by her cage again when Kronos calls to him, saying that Caspian is dead and MacLeod is coming. Cassandra assumes that Methos had lied to her earlier about MacLeod being dead, though (since Methos knew that Kronos sent both Caspian and Silas to kill MacLeod) Methos was probably being truthful and really believed MacLeod was dead. Silas is left to guard Cassandra, and Kronos tells Silas to kill her if MacLeod gets near.
Kronos and Methos meet MacLeod in another part of the base. MacLeod accuses Methos of setting him up; Methos says nothing. Kronos offers MacLeod a deal: "Fight and Cassandra dies. Give up and she lives." MacLeod replies, "I think she'd rather be dead," and prepares to fight. Kronos tells Methos to go tell Silas to kill Cassandra. As Methos leaves, MacLeod calls after him, "Methos, don't do this!" and Methos replies, "Like you said, MacLeod, I go with the winner."
However, at the cage, when Silas drags Cassandra out, Methos draws his own sword and challenges his former brother, saying, "You know nothing about me!" They begin fighting, and eventually the two pairs of combatants (Kronos and Duncan, and Silas and Caspian) end up in the same place. Methos and Duncan are victorious, and after the quickenings subside, Methos is on his knees weeping beside the body of Silas. Cassandra comes forward and picks up Silas's axe and holds it over Methos's exposed neck, crying out, "Now I'm supposed to forgive you?"
MacLeod calls, "I want him to live!" She starts to strike; he calls again, "Cassandra, I want him to live!" Eventually, after (presumably) some thought and with a glare for MacLeod, she drops the ax then slowly walks from the shadows up into the daylight and disappears.
Later, MacLeod asks Methos about Cassandra. "One of thousand regrets, MacLeod," Methos replies, starting to walk away. "One of a thousand regrets."Six months later (May 1997), when the demon Ahriman is making itself known, Richie mentions Cassandra to MacLeod, and Cassandra's face and voice appear onscreen, repeating the words of the Prophecy.
In "Prophecy", Cassandra usually seems calm and controlled. However, in her obsession with fulfilling the prophecy, she manipulates Duncan. She behaves seductively when he is thirteen, allowing him to see her naked in a pool and kissing him goodbye. When they meet in 1996, she uses the Voice on him, which he does not like.
When she reappears in Comes a Horseman she is obsessed with killing the Horsemen and has lost her calm. She is impatient and impulsive. She believes Methos is a liar and that he is using Duncan, and she does not accept any evidence to the contrary, insisting repeatedly that Methos has to die. Only at the very end of Revelation 6:8 does she stop to reflect. When she walks away, she seems angry with Duncan as well as with Methos, so she has a way to go before acceptance.
She seems to rely on her magical Voice instead of her sword. She gives an eerie scream to stun Roland and make him drop his sword. She is easily disarmed by Kronos, who is immune to the Voice, and when she senses an Immortal outside her hotel room, she opens the door while leaving her sword all the way on the other side of the bed.