The Earl of Millennium
The series' main villain, also known as "the Earl of Millennium" or "Duke Millennium" (though Road affectionately calls him "Millenie"). He's an ancient sorcerer who manipulates grieving people into creating Demons—Akuma—by posing as their dead loved ones. His endgame is nothing short of world destruction. He's allied with the Noah Clan, who treat him as family despite his apocalyptic agenda.
Creator Hoshino drew inspiration from historical legends of immortal alchemists and preachers—possibly the Count of St. Germain or Nicolas Flamel—figures rumored to still be alive somewhere. The character also echoes Dorian Gray, which fans have connected to the series title itself.
Visually, he's unmistakable: a rotund Victorian gentleman in a cape and top hat with an enormous, unnaturally fixed grin plastered across his face. His eyes hide perpetually behind pince-nez spectacles. In the manga, nearly every line he speaks ends with a heart symbol. The anime opts for unfailingly polite Japanese speech instead.
He's basically two people in one. Around the Noah, he's warm and playful—practically a doting uncle, especially toward Road. But flip the switch and he becomes sadistically cruel, treating people's lives as toys to destroy. It's genuinely unsettling how seamlessly he shifts between these modes.
As for combat, his weapon of choice is an umbrella named Lero, though he can also unleash massive explosions of dark energy. He's summoned a massive black sword that directly opposes Allen's Crown Clown. There's also some gag material suggesting he has multiple ears hidden under those various hats he collects—yes, he changes hats constantly, each one decorated differently.
Content compiled by AnimeList.moe from publicly available sources.