In his lifetime, Nastasio was the son of a Galician squire near Oviedo. Talented in the art of battle, he was promoted to Captain of Horses with only 26 years, having constantly proved himself in battle against the Muslims. He eventually set off to France, becoming a freelancer and achieving quite a reputation as a warrior and leader. When he entered the service of the Baron of Aire in 1006, he had no idea that he was dragged into a conflict between a Ventrue and a Lasombra. He ended up staking and burning the Lasombra, impressing his future sire enough to grant him the Embrace.
Afterwards, he traveled the world, selling his sword for various Ventrue lords, never regretting his unlife. In 1205, he was recruited by Archbishop Monçada to fight against the Muslims in the Shadow Reconquista. He proved himself in battle and was granted his hometown as princedom. He managed to stave off the Anarch Revolt and eventually became one of the first Justicars of the Camarilla.