Irina

Irina is one of the original Denali “sisters” and an originator of the myth of the succubus. She is a “vegetarian” and leads a very peaceful lifestyle. She, like her sisters, loves men – all men, even human men. She and Laurent had a relationship before he was killed by the shape-shifters. Irina was killed by Caius after giving false information to the Volturi about Renesmee Cullen.

Breaking Dawn
In Breaking Dawn, it is revealed that she Tanya, and Kate were orphaned by the Volturi because their mother was harboring an immortal child, a human child that was turned and therefore cannot learn to control themselves due to their primitive minds. Irina did not appear at Bella and Edward's wedding unlike the others of the Denali coven, because she was still upset at the wolves for killing Laurent. Later as Bella, Jacob, and Renesmee were hunting, Irina watches them from a distance. She sees what she thinks is an immortal child that Bella has created. Seeing this Irina flees, but not before Bella sees her. Bella tries to run after Irina, but by the time she does Irina has already fled. Meanwhile Bella, Jacob and Renesmee return to the Cullen's house to tell them about Irina. Bella comes to the conclusion that Irina believes that Renesmee is one of the ppimmortal children]]. Irina eventually decides to go to the Volturi to tell them about Renesmee. Irina is next seen with the Volturi when they arrive in Forks. She is called upon by Caius to bear witness to Renesmee. Irina comes to the conclusion that she was wrong and that there was no reason for the Volturi to be there and that she doesn't want the Cullens to get hurt and that she would take full responsibility for her actions. Meanwhile Caius signals the guard and Irina is attacked and dismembered in front of all the vampires present. Caius justifies this by sayinng that "now she has taken full responsibilty". Caius merely looks on and throws set Irina ablaze, nearly causing Kate and Tanya to attack.

Physical Description
Irina is described as being a vampire with chin length silvery blonde hair.