Petrodon began his career when he was made an Archon by Justicar Castillo. He is the only known Justicar to have settled a permanent haven in the U.S, where he operated mainly from Seattle. He was assassinated in Chicago in late 1997.
Born as Count Alonso Cristo Petrodon de Seville, Petrodon was struck with the plague in 1348; the Nosferatu Cristo Embraced him to save his life. Although Petrodon had been exceedingly proud of his looks in life, he quickly adapted to his Nosferatu visage. In 1437, Petrodon Embraced Julio Martinez, who served him well until a mission in which Petrodon sent Julio to Mexico City, where the Sabbat had recently taken power. Julio was captured, tortured, and interrogated by the Nosferatu antitribu. Seemingly broken, Julio joined the ranks of the antitribu, although his blood bond to Petrodon may have continued to influence his actions.
Petrodon was more successful when he Embraced Cock Robin in 1757. Although sire and childe were separated for over a century, they were reunited in the 1990s when the Nosferatu of New England, commanded by Petrodon through his messenger Prudence Stone, overthrew the Nosferatu spymaster Stanford Warwick, the Prince of Providence, Rhode Island. Cock Robin would continue to serve his sire as a fiercely loyal Archon for the brief remainder of Petrodon's existence. Petrodon also took on non-Nosferatu underlings over the centuries, such as the Brujah Carlak, who served under him as an Archon from 1946 to 1972. Carlak left Petrodon's service when he replaced his own sire as the Brujah Justicar, thanks in part to Petrodon's recommendation.
In the modern nights, Petrodon earned a reputation for brutally cracking down on the Anarchs. He is known to have attempted to prosecute Salvador Garcia for allegedly committing diablerie. His anti-Anarch efforts increased in 1984, when he was ordered (presumably by the Inner Circle themselves) to crack down on the Anarch Free States. Petrodon's sympathetic tendencies (relatively speaking, for a vampire and a Justicar) occasionally overrode his intense loathing of the Anarchs, but only briefly. For instance, he once recommended leniency for the condemned Anarch Kaly after she showed remorse, only to castigate the city's Prince after her trial for having granted her clemency.
In 1997, the Kindred sculptor Leopold created a statue for Petrodon that depicted the Justicar as he had appeared in life as a mortal. Leopold had secretly been conspiring with the Tremere antitribu Nickolai and the minor Giovanni scion Benito Giovanni. The conspirators used Petrodon's awe at the statue as the distraction they needed to kill the Justicar. After Petrodon's murder, Cock Robin succeeded him as the Nosferatu Justicar, and Justicar Carlak resigned from his post. All three conspirators in Petrodon's death were eventually slain: Leopold slew Benito while possessed by the Eye of Hazimel, Leopold and the Eye were slain by a group of potent vampires during the Camarilla's siege of New York City, and Nickolai was personally executed by Cock Robin.
Petrodon is described as being 5th generation in The Players Guide and the Vampire Players Guide Second Edition; the former gives his name as "Petrondon", though the latter gives his name correctly. His childe Julio Martinez is thusly given as 6th generation in The Chaos Factor. However, Petrodon's other childe, Cock Robin, is described as being 7th generation in both Children of the Night and Encyclopaedia Vampirica. In order to reconcile these discrepancies, either their respective generations should be one higher, or else both Petrodon and Julio must have lowered their respective generations via diablerie at some point.