Void Double

Void Double is a Technique used by Ace and is obtained from defeating Absolution. When obtained, it allows Ace to create a stationary shadow copy of himself that attacks with Ace (Does the same damage as Ace aswell) and can teleport to one time.

The main uses for this technique are extra damage to strong enemies/bosses, and is super effective against Lethal Tempo, allowing you to attack multiple parts at once. The ability to teleport to the clone makes it very useful as a "Get out of jail free card" allowing you to get out of the way of projectiles instantly or let you re-do a jump without losing any health or armor.

Surged
Surging Void Double allows Ace to teleport between places. Keep in mind it creates a new double exactly where you were every time you activate it so spamming the teleport while in the air will only slow the descent, not stop it.