|Sources||Avacyn Restored and Sorin's Homecoming, see external link below|
The Creation of Avacyn
The vampire planeswalker Sorin Markov created her and tasked her with protecting the plane. Through her, the magic of faith would create true power to fend off the darkness. The Church of Avacyn rose from the power Sorin invested in her.
Avacyn's purpose is to maintain the balance on Innistrad. Without her the equilibrium between humanity and the dark forces would be broken, with the resulting extinction of humanity at hands of the vampires or werewolves and the triumph of demons over the plane, all of which would lead to the vampires resorting to cannibalism once humans and the other species were extinct. (Also, eventually resulting in extinction.)
Disappearance of Balance
Sorin knew never to expect peace and harmony on his shadowed homeworld, but he thought he had arranged a kind of effective equilibrium, a set of safety measures designed to keep one side of the scale from ever tipping too far. He trusted that this system would maintain itself without his intervention and left the plane in the hands of his creation.
However, not long ago, the demon Griselbrand defiantly came to the Helvault and challenged Avacyn to combat. Avacyn and Griselbrand battled for days, out of view of all but Avacyn's host, the Lunarch, Mikaeus, and his most trusted bishops. Finally, in an act of desperate effort, Avacyn used all of her remaining strength to drive Griselbrand into the Helvault. As his final act, Griselbrand threw his spear and impaled his angelic warden. The binding spell backlashed as she was impaled, and Avacyn was drawn into the Helvault along with the demon. Avacyn was imprisoned in the Helvault alongside every other demon that was trapped within. The angel's disappearance not only endangered the humans of Innistrad, it smashed the carefully-constructed balance between humanity and the creatures of the night.
Liliana Vess visited Innistrad in the hopes of destroying Griselbrand, with whom she had made a demonic pact that would result in her soul's enslavement. To these ends, she opened the Helvault by forcing an ultimatum on Thalia, its guardian; either she'd destroy the rock, or her soldiers would die. This result in the release of both the demons and Avacyn, restoring mankind's line of defenses against the darkness.
The people of the remote village of Gatsaf appealed to Avacyn for aid in breaking the lycanthropic curse after her return. Avacyn appeared to them in Gatstaf Grotto where many had gathered to strike down what they saw as their scourge. Avacyn's message was short and simple. She could not break the curse of lycanthropy, she said. The curse mingles the human spirit with the spirit of the wild, and the wild spirit could not be destroyed without also destroying the werewolf's humanity. So those afflicted with the curse would forever have it. However, Avacyn offered the Gatstaf werewolves a special place at her side. If they promised to serve as guardians of humanity, she would transform their curse, fusing the two warring aspects, and allowing them to dwell in the light of her blessing. The lycanthropes at the Grotto accepted her offer, and she transformed them into the wolfir. In a powerful wave of spells that would become known as the cursemute, Avacyn's magic spread through the plane, transforming not just many werewolves but many of the world's foul curses. The wolfir emerged as a new race of great wolf-creatures dedicated to the principles of the Church of Avacyn.
Quoted or referred to:
- Avacyn's symbol appears in art throughout the Innistrad block. 
- Ancient Grudge
- Angel of Flight Alabaster
- Archangel's Light
- Avacyn's Collar
- Avacyn's Pilgrim
- Bonds of Faith
- Disciple of Griselbrand
- Divination (Dark Ascension)
- Faithless Looting
- Mask of Avacyn
- Moon Heron
- Niblis of the Breath
- Peel from Reality
- Reaper from the Abyss
- Ranger's Guile
- Smite the Monstrous
- Unhallowed Cathar
- Vault of the Archangel
- Doug Beyer. (January 11, 2012.) "Sorin's Homecoming", Daily MTG, magicthegathering.com, Wizards of the Coast.
- Doug Beyer. (January 18, 2012.) "The Prison of Silver", Daily MTG, magicthegathering.com, Wizards of the Coast.
|Expansions: Innistrad | Dark Ascension | Avacyn Restored|
|Provinces: Gavony | Kessig | Nephalia | Stensia|
|Planeswalkers: Liliana | Garruk | Sorin | Tamiyo | Tibalt|
|Characters: Avacyn | Griselbrand | Gisa and Geralf | Mikaeus | Thalia | Odric|
|Others: Vampires | Werewolves | Zombies|