Nero Gladius

Nero Gladius(ネロ・グラディウス; Nero guradiusu), also known as the traitorous knight of the Crimson maiden, is a supporting character in Highschool DxD: Яe-birth. The second Knight in Nemesis Gremory's Peerage, he's both Aria's and Nemesis's boyfriend/lover, ichijou's second mentor and one of the bodyguards of Alice Gremory.

A former member of the church and an ex-crusader, Nero carries the Demon Sword of Treason Clarent as well as artificial sacred gears created by the heavens known as Holy Arms. He also was the original wielder of the dragonslaying sword Ascalon before passing it down to Ichijou so that he could fight Evelyn Livan Lucifer. He was a secondary antagonist and ichijou's own Nemesis during the events of Volume 3, The Cheesy Sekiryuutei and the Crimson Kings.