Bree Tanner and Diego were both newborn members of the Seattle newborn army, created by Victoria. They became a couple one week before their battle against the Cullens. They died at different times; Diego was tormented to death by Victoria for discovering that sunlight didn't hurt vampires, like they were told; and Bree was accused of being a criminal and executed by Felix.
- "Diego grinned at me, his face beautiful with light, and suddenly, with a deep lurch in my stomach, I realized that the whole BFF thing was way off the mark. It was just that fast... But even though Diego looked like his normal self again - not made of blazing light anyway - I knew he would never look the same to me. That tingly sensation in the pit of my stomach was still there. I had a feeling it would be there permanently."
- ―Bree on Diego[src]
Bree Tanner lived with her abusive father for most of her human life. She was led to believe that her mother left her at the tender age of two. In reality, Bree's father killed her mother. After numerous years of abuse, Bree could no longer endure her father's abuse and ran away from home, completely disregarding her father's warning of starvation. Bree was forced to either steal food or eat out of garbage cans. Three weeks after deserting her home, Bree encountered Riley. Marveling at his beauty, Bree accepted the "burger" he had offered. It was at this point that Riley brought her to Victoria to be transformed into a vampire.
After her transformation, Bree was brought into the army. While the members fought and killed each other for sports, she sought solitude and tended to keep to herself and hide behind a gifted vampire named Fred, who could avoid unwanted attention with his power. This method kept her alive for the next few months.
- "He ducked close and kissed me - just a peck, but right on the lips. The shock of it zinged through my whole body."
- ―Diego's kiss[src]
Diego grew up in a lower-class, single-parent home in LA with his mother and little brother. He worked part-time jobs to help out while attending high school, and had a goal in life: to leave his street life and go to college as well as help his brother get a proper education. He managed to stay out of trouble, but when his little brother failed to do so and died as a consequence, Diego tried to avenge him. That night, Diego killed his brother's killer and then was cornered by armed enemies. Just then, Riley Biers came to his rescue and asked if he wanted a new life. Riley escorted Diego to Victoria, who transformed him into a vampire. After a while he befriended a fellow newborn, Bree. The two became fond of one another and became mates. However, Diego learned of information regarding Riley that would have jeopardize the loyalty of the Victoria's army. Because of his knowledge, Riley killed him in an attempt to silence him.
In the next eleven months of his new life as a vampire, Diego acted as the most responsible member, always looking after his lesser tamed mates, even if they didn't want to be looked after. Part of Diego's obedience and loyalty toward Riley came from Riley having been his only friend during Diego's vampiric life. Riley, in return, was very fond of him.
The Short Second Life of Bree Tanner
- Main article: The Short Second Life of Bree Tanner
During a night out, Bree and Diego separated from two other ruthless vampires - Kevin and Casey - who were fighting for the blood of a victim. The two bonded and, in the process, fell in love. Bree felt very safe around Diego because of his generosity. In the next morning, they discovered the true effects that sunlight had on vampires and that they could not be harmed by wooden stakes, and planned to tell Riley of their discovery. Diego further encouraged their love by kissing Bree, effectively showing her his genuine feelings. Diego went to inform Riley alone and upon hearing of his discoveries, Riley took him to Victoria who decided to kill Diego before tormenting him to extract all information out of him. To cover his tracks, Riley pretended and informed Bree that Diego was with the one they call "Her" (Victoria) when in actuality Diego was tortured by Victoria and Riley before being murdered.
- Main article: Eclipse
When Bree agreed to participate in the army's assault, she had high hopes that Diego would be present; however, to her dismay, Diego wasn't anywhere to be found in the field. It was then she realized Riley and Victoria had killed Diego to silence his words to the newborns regarding the sun. After Victoria's army was disbanded, Bree was executed by the Volturi in front of the Cullen family. The Cullens begged for Bree's life, explaining that they would take responsibility for her; however, the Volturi refused to accept persuasion and the Cullens were unable to save Bree from her unfortunate death. However, Bree was content to know that her enemies were willing to defend her.