Gregori

The Qwaser of Gold, who is the leader of the Adepts whose true face has never been seen. His only real appearance in the story has been through possessing Tomo using a "golden nail" implanted somewhere in her chest that constantly drains her Soma and strengthens the Qwaser himself. He was the one who killed Sasha's older sister Olja, and apparently used Sasha's anger at him to launch an entire Xanatos Gambit spanning years just so he could later use a large-breasted Japanese schoolgirl to gain the Blade of Maria through a special Faberge Egg and somehow use its power to change the world in his image.

There are hints in the anime and the manga that this Qwaser is actually a Catholic cardinal named Gregori.