Unicorn

Unicorns are magical creatures living in Arden. They were hunted to extinction by Queen Estelle and her Gemmer army. The last unicorn was trapped in stone for 300 years, but Claire woke it from the rock with her Gemmer magic. Sophie turns into a unicorn in Book 3: Fire in the Star.

History
Unicorns were magical creatures living in Arden, but Queen Estelle and the Gemmer army hunted them all to extinction, all except for one.

When Queen Estelle tried to kill the last unicorn, her brother turned her into Queen Rock, with the help of the last unicorn. Consequently, the last unicorn was turned into Unicorn Rock.

The Unicorn Quest
Mira Fray tried to awaken the last unicorn but failed because she used Sophie's blood, who wasn't a Gemmer.

Claire Elaina Martinson successfully awakened the last unicorn that chased all the wraiths away and healed Sophie.

Secret in the Stone
During the second book, the last unicorn of Arden is injured and travels to Woven Root to heal. He experiments with Sena's parents in the seams of the world, and gets himself and Sena's parents trapped in the Way Between.

Claire figures out that Sophie was turning into a unicorn.

Fire in the Star
In the third book, the unicorn returns to Arden. He goes to Nadia and he gets the guilds to agree to crown Nadia. However, Estelle and her Royalists find him and kills him before he can bless the Crown of Arden.

Later in the book, Claire and Sophie awaken the moontears and they turn into unicorns.

Abilties
Healing: Unicorns possess the able to heal. At the end of the Fire in the Stars, they heal Petrified Forest, and other parts of Arden

Magic Enhancing: Unicorns are the strongest magic in Arden. They are even able to enhance guild magic. Because of this, during "Craft Era" Arden, aritifacts containing unicorn magic in them, were cataloged by which guild's territory it came from.

Door Opening: Unicorns are able to open any door, including doors to other worlds.However, to create a door to another world, one also needs create a phyiscal door, also known a portal, using materials associated with each of the four guilds. An example of this is the Old Stone Well, which has a wood ladder (tiller material), a stone base (gemmer material),