Diego appeared in the first chapter, along side Selene, both of whom were 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 bought the weapons from, was 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 left as quickly as possible by limo, the breeze shifted direction, leaving Diego upwind of the Lycans, who immediately caught his scent.
Before Selene could intervene, an unknown assailant made her move, throwing a silver shrapnel grenade at the trio of Lycans. The assailant then threw the next grenade at Diego, injuring him and throwing his body near the Lycan trio. A third grenade was thrown at Selene before she moved to help Diego. Their assailant then brought out a flamethrower, killing two of the Lycans before turning their attention towards Diego. Selene opened fire at their assailant, but could not stop the attack, and the injured Diego was consumed by the flames.
After his death, and after she has recovered from her own wounds, Selene crusaded to track down their unknown assailant. Her first lead took her back to Florescu, who she realized must have known something was going to happen. Once she knew everything he knows, Selene, Kahn and a team of Death Dealers, (including Death Dealers, Nathaniel, Mason, Rani and Yoshio), stormed Florescu's country compound, whom Diego's murderer, a female Lycan called Leyba, had usurped control of. During the assault, Yoshio was killed by one of the compound's booby traps, and Selene finished 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|