A being from the future, who has returned with the intention of preventing the Momentum-driven Apocalypse that ruined his world

He is the true form of the Yliaster Emperors, each representing a tragedy in his life. Lucciano - his childhood - was the despair of losing his parents, Placido - his adulthood - was the despair of losing his love, and Jose - his senior years - was the despair of being the only human left alive. He, however, wasn't alone and met Zone, Antimony, formerly known as Dark Glass/Bruno, and Paradox, together working for the bleak future. Aporia shortly followed Antimony and Paradox to death through old age, asking Zone to stop their world from becoming reality before he died.
In the WRPG, he comes about when the three Emperors come their powers and recreate his body, which he uses to continue the duel with Yusei, tearing apart the City around him.

After he is defeated by Yusei, the Arc Cradle is supposed to have vanished, yet Zone tells him that something has changed and their plan can proceed. Despite being damaged from the duel with Yusei, Aporia pleads to Zone to let him help and repairs are made to his body to enable that help.