Dusk Bringer

Dusk Bringer (also known as Twilight, Asmodeus, and Diablos) is Dio's 4th job, where he draws his ultimate strength to fight. It was released in the Korean server on October 11th, 2012.
Like the other AP characters, Dio retains the ability to possess abilities of Stygian, Drakar, and Leviathan all at once. However, in order to access his Dusk Bringer abilities, he must go either fully Weapon or Devil Pose, not hybrid.
With Dio's Devil Pose unsealed, he is granted additional effects to many of his previously learned skills, such as creating barriers to protect himself, allowing his Rake Hand to destroy AP/MP or makes his enemies bleed, or extend the number of energy balls he can create.
With Dio's Weapon Pose unsealed, he is granted a moveset that not only grants Dio incredible speed, but also allows Dio to chain his already deadly support weapons with an even deadlier precision.