He is one of Aporia's three embodiments of despair, one of the Three Pure Nobles of Yliaster, and one of the main antagonists of the second season, with Lucciano and Jose. As one of the Three Nobles, he is working to complete the Grand Design. He impatiently started several plans of his own agenda in attempt to force the completion of the circuit by attacking the WRGP preliminaries with the Diablo Duelbot Army. Yusei Fudo thwarted the invasion by defeating him, and after being repaired Primo began supporting Jose's plan by joining the WRGP as a part of Team New World.
Placido is one of the few left-handed Duelists in the franchise, along with his other embodiments as well as Paradox and Bruno.