Originally a normal human, Cordelia began receiving prophetic visions from The Powers That Be in the Angel episode, "Parting Gifts." The visions usually consist of ambiguous imagery of forthcoming attacks on innocents or various demonic disasters. Cordelia used this imagery to help Angel prevent them from happening.

Cordelia was the mother of a brood of Haxil Beast spawn in the episode "Expecting." When pregnant with them, she gained a telepathic connection with the children and their father, who used it to control her. In the episode "Epiphany," Cordelia was forced to be the host of an unborn Skilosh demon, which granted her a working third eye in the back of her skull until it was removed.

In the episode "Billy," Cordelia claims that as a cheerleader, she need only be shown a move once before being able to mimic it, and demonstrates this by successfully copying a series of combat moves Angel is teaching her, and manages to corner him as a result. In the episode "Supersymmetry," she continues to learn how to fight under the instruction of Connor.

To combat the pain and trauma the visions give her (which would eventually kill a human), Cordelia became part-demon in the episode "Birthday," giving her resistance to their harmful effects and other powers including levitation and the ability to purify ("heal") the souls of those affected by demons and light related powers, which she has on one occasion used as a nightlight. Her visions were now less ambiguous and more surreal. Because of this action of accepting demonhood, Cordelia was deemed a higher being and ascended to a higher realm. There she was able to wage the war on evil in a new way as a higher being in paradise with The Powers That Be, as seen in the episode "Tomorrow."

When she returned to this world, however, there was a hitchhiker that came along. This came in the form of Jasmine, a former higher being that would possess Cordelia early on in Season Four. At first, only slight irrational differences were seen in "Cordelia", such as sleeping with Connor (in the episode "Apocalypse, Nowish"). Eventually, this night of passion between the two would result in a new body formed for Jasmine after an incubating period. Jasmine could also cast spells while possessing Cordelia, and is able to hold up against (post-"Grave") Willow in a magical battle.

In the final season, Cordelia apparently creates a solid astral projection of herself to help Angel in the episode "You're Welcome," likely aided by the Powers That Be.