Marcello was originally the bastard son of a Giovanni and served his period as a ghoul to a family member, before the Tremere Councilor responsible for South America, Xavier de Cincao, threw his eye on him.
Cincao embraced Marcello as a means of revenge against the Necromancers and the first thing Marcello did once he ascended into his position was to ban all members of his former family out of his city. Furthermore, he provides his sire with plenty of information about the customs and necromantic rituals of his family.
He is dedicated on further strengthening the alliance with the Toreador that has allowed the Camarilla to prosper in the otherwise hostile environment of South America. Rumors about his resemblance to certain Giovanni family members and his presumed dealings with the Sabbat still circumstance, but failed to severely damage his reputation.