Diego appears in the first chapter, along side Selene, both of whom are on a reconnaissance mission in Statue Park, observing dealings between the Lycans and human arms dealer, Leonid Florescu, as Selene was tipped off that Florescu, from whom the Vampire Coven buys the weapons from, is also dealing weapons with the Lycans. Diego was hidden behind the granite bust of a unnamed Communist leader, directly opposite to Selene's location in the park. As Florescu leaves as quickly as possible by limo, the breeze shifts direction, leaving Diego upwind of the Lycans, who immediately catch his scent.
Before Selene an intervene, an unknown assailant makes their move, throwing a silver shrapnel grenade at the trio of Lycans. The assailant then throws their next grenade at Diego, injuring him and throwing his body near the Lycan trio. A third grenade is thrown at Selene before she move to help Diego. Their assailant than brings out a flamethrower, killing two of the Lycans before turning their attention towards Diego. Selene opens fire at their assailant, but cannot stop the attack, and the injured Diego is consumed by the flames.
After his death, and after she has recovered from her own wounds, Selene crusades to track down their unknown assailant. Her first lead takes her back to Florescu, who she realizes must have known something was going to happen. Once she knows everything he knows, Selene, Kahn and a team of Death Dealers, (including Death Dealers, Nathaniel, Mason, Rani and Yoshio), storm Florescu's country compound, whom Diego's murderer, a female Lycan called Leyba, has usurped control of. During the assault, Yoshio is killed by one of the compounds booby traps, and Selene finishes off Leyba, avenging Diego's death.
- Diego’s name indicates that he is from either a Spanish and Italian background, making his nationality European.
|Selene - Lucian - Sonja - Viktor - Kraven - Nicolae - Soren - Leyba - Brother Ambrose - Grushenka - Ilona - Leonid Florescu - Marcus Corvinus - Yoshio - Diego|
|Vampire - Lycan - Immortal - Human|
|Silver Mine - Castle Corvinus - Crypts - Strasba - Keep - Ördögház - Budapest|
|Death Dealer - Vampire Elder - Budapest Coven - Blood Memories|