Avery Lazar appears when her father Eugene Lazar is appointed as Headmaster of St. Vladimir's in Blood Promise. At first, Lissa Dragomir thought that Tatiana Ivashkov had sent a beautiful, perfect friend that would spy on her and train her to the Queen's standards. At first, she wasn't very friendly to Avery. When Lissa overhears Avery's father saying some pretty harsh things, she slowly begins to warm up to her.
One school morning, Avery pulls off a fire alarm and gets Lissa and Christian Ozera to leave school and come with her to Adrian's room in guest housing. Avery appears to have a crush on Adrian Ivashkov.
She encourages Lissa to spend a weekend at the Moroi Royal Court with her. With them, they bring Jill Mastrano and Adrian Ivashkov. When Lissa drunkenly kisses Aaron, she doesn't make a big deal out of it. Although, Jill thinks differently. When back at St. Vladimir's Academy, Jill accidentally tells Christian. Rose Hathaway is watching through the spirit bond, and after Christian tells her off for kissing Aaron, Avery pushes Rose out of Lissa's mind. Rose didn't know what happened. She just thought it was a fluke of the bond. But, unknown to Rose at the time, Avery is another spirit user. Another time, when Rose is watching Lissa through the spirit bond after Christian breaks up with her, Avery says something rude to Rose and pushing her out of the bond. This is when Rose realizes that Avery is a spirit user. Avery did a decent job disguising herself as an Air user, also masking her aura from Lissa and Adrian.
Later on, she pretends to tell Lissa not to be up on the window sill but she's using compulsion on her to make her jump out the window. Oksana reaches into Rose's mind while she goes to Lissa to help fight Avery's compulsion. Avery tries to distract Rose by creating an illusion of Dimitri Belikov as a dhampir but Rose breaks through it. When Avery was knocked out by the combined magic of spirit users, all the spirit flooded into her and fried her, making her go crazy. When Adrian and Rose discussed Avery's motives, and figured out that Avery had wanted Lissa to look unstable and crazy in case Avery couldn't raise her back to life, making her shadow-kissed.
Avery's Spirit Induced Motives
Avery first discovered her element when she witnessed Simon die in battle. She unknowingly brought him back to life with spirit, creating a Shadow-kissed bond between the two. Once she realized what happened, she killed her brother, Reed Lazar, and also made him Shadow-kissed as well. The more people she had shadow-kissed, the more spirit power she could use. So when she befriended Lissa, she wanted to kill Lissa, but bring her back to life as well, making another spirit user shadow kissed. What Avery did was very unbalanced and the slightest thing could mess it all up.