Killaura is a perk. Perks are unlocked through contracts and Perk Amulets, and upgraded as described on the Perks page.
Levels
Level text as shown in the perk menu in game.
- I: All Killstreak Perk Streak requirements are reduced by 10%.
- II: All Killstreak Perk Streak requirements are reduced by 20%.
- III: All Killstreak Perk Streak requirements are reduced by 30%.
- IV (with a Perk Pusher): All Killstreak Perk Streak requirements are reduced by 40%.