Número Cinco was the alias of an employee at Wolfram & Hart as well as a former wrestler and Champion. Alongside his four brothers, he was one of the Hermanos Número.
With his brothers, he fought evils such as the Diablo Robótico and also defeated Spike in 1947, chasing him out of Los Angeles. In 1953, his four brothers were slain by Tezcatcatl, an ancient Aztec demon who ate the hearts of heroes in order to remain in the world.
In 2003, Tezcatcatl returned on the day of the dead, forcing Angel to recruit Numero Cinco to help him defeat the demon. Angel's willingness to fight was hampered by own self-doubt after Tezcatcatl apparently rejected his heart. As he visited his brother's grave, Tezcatcatl appeared, causing Numero Cinco to claim that he had swallowed the talisman the demon sought in an attempt to provoke it into killing him. As Angel arrived on the scene, Numero Cinco's brothers were restored to life by his bravery, Angel subsequently collaborating with the four of them to defeat the demon. As Numero Cinco lay dying, he revealed to Angel that he had hidden the talisman in the coffee thermos on his brothers' memorial headstone, subsequently assuring the vampire that the demon had only rejected his heart because of his vampire status. With that, Numero Cinco died with his reborn brothers, Angel silently watching as they returned to their afterlife.