Critical Ascensi0n is the tier 6 skill in Zer0's Sniping skill tree. When scoring a critical hit with a sniper rifle you receive bonus critical hit damage and regular damage with sniper rifles. This skill can be stacked up to 999 times, but will begin to fade somewhat rapidly if a critical hit has not been scored in a few seconds.
- Critical Hit Damage: +6% per stack
- Sniper Rifle Damage: +5% per stack
- The buff lasts for 6 seconds before beginning to fade, and thereafter fades at a rate of about one stack every 2 seconds.
- Missing an enemy or hitting an enemy non-critically does not cause the buff to fade.
- Critical Ascensi0n is extremely useful against bosses and slow or stationary enemies with easy critical hit spots, as the buildup of stacks can easily double or triple damage dealt while whittling down a boss or tough enemy's health.
- Sniper rifles that fire multiple projectiles per shot, such as the Skullmasher, will add multiple stacks of Critical Ascensi0n per pellet if more than one scores a critical hit.
- Opening a menu (such as a map, inventory, or mission log), using a vending machine, talking to a mission giver, or dying will remove all stacks.
- Performing melee, or throwing a grenade does not affect stacks. Switching to a weapon that is not a sniper rifle will remove all stacks, but switching to a different sniper rifle will retain stacks.
- While believed to be impossible, an assassin can get the maximum stack of 999 if there is a Gunzerker with a Hoarder class mod equipped in the game, allowing ammo regeneration which then makes it possible to achieve 999 stacks.