Morrigan is a Witch of the Wilds. one of innumerable sorceresses whose legends originate in the Korcari Wilds. She is called upon to leave her home to become a companion to the Warden. Morrigan can be romanced by a male Warden, and can also teach the Shapeshifter specialization.
Morrigan is the daughter of Flemeth. the legendary Witch of the Wilds who has reputedly given birth to scores of daughters and has lived for centuries, though Morrigan is unwilling or unable to confirm Flemeth's true origins. Whatever Flemeth's history, Morrigan was raised by her in isolation from civilization. Flemeth instilled a distrust of humankind in Morrigan, strictly forbidding her from venturing out into settlements. As such, Morrigan sought solace among nature and the animals of the Korcari Wilds, into whose forms she would often shapeshift.
When she reached a sufficient age, Morrigan would occasionally assist Flemeth in eliminating threats to them. If templars hunted the pair, Morrigan would often play the part of the innocent girl in fear for her life, while in reality leading the men to her mother, and thus to their doom.
Dragon Age: Origins
“We now have a dog and Alistair is still the dumbest one in the party.” — Morrigan
Morrigan first encounters The Warden in the Korcari Wilds, following them in animal form and later leading them to Flemeth, who held ancient Grey Warden documents necessary for the completion of their Joining. Following the Battle of Ostagar. Morrigan helped nurse The Warden and Alistair back to health, later accompanying them on their quest at the behest
After receiving and examining Flemeth's Black Grimoire. Morrigan claims that her mother plans to possess her body in order to prolong her own life. To prevent this, Morrigan asks the Warden to slay Flemeth.
Note: You may need to complete one of the main quests first to get Morrigan to ask you to kill Flemeth.
On the eve of the Battle of Denerim. after the Warden learns from Riordan that a Grey Warden must die in order to defeat the Archdemon. Morrigan offers an alternative. If she can conceive a child with a Grey Warden, the Achdemon's soul will pass into the unborn child rather than the Grey Warden who strikes the killing blow.
If The Warden rejects the ritual: The Warden rejected the ritual, enraging Morrigan. The witch shapeshifts into a Wolf and abandons her companion to their fate.
If Alistair completed the ritual: Though The Warden did not take up Morrgian's offer, Alistair reluctantly underwent the ritual despite the hostility between Morrigan and him.
If Loghain completes the ritual: In the place of The Warden, Loghain Mac Tir. recently recruited into the Grey Wardens as penance for his crime at Ostagar, underwent the ritual with Morrigan.
If The Warden completes the ritual: The Warden agreed to Morrigan's request. The two spent the night together, with the pregnant Morrigan mysteriously vanishing after Ferelden's victory at the Battle of Denerim.
See Epilogue for the full details of Morrigan's potential fates..