Placido is a cold, unloving android with a determination to kill Yusei Fudo. He is part of the tenor trio along with Lucciano and Jose, and thus wields his own Machine Emperor, Wisel. Through out his appearances, he is the most hands-on of the trio, to the point of assaulting Yusei(and by farther extent Dark Glass) himself. Unlike Lucciano and Jose who await the circuit to be completed the way it's suppose to be, Placido wants to straight out kill Yusei and force the circuit into completion.
He also has a very interesting transformation in episodes 107-110, in which he merges with his D-Wheel to create "Ultimate Placido"(sometimes referred to fans as Placycle).
During episode 110, Placido gets dissected from his D-Wheel by Shooting Star Dragon in his duel with Yusei. Seemingly destroyed, he later returns about 10 episodes into the future, fixed by the trio's god known as Z-One. Finally he gives into Jose's plan about joining the WRPG, and thus seemingly is the only duelist for Team New World up until the finals. After Granel is wrecked, he fuses along with others into Aporia.
It is later revealed that Placido is actually Aporia's middle aged years.