Build up momentum for 20 seconds. While active, hit with 4 light or heavy attacks to turn this into Assassin's Will and fire a spectral bow to deal Magic Damage. Also grants Minor Berserk, increasing your damage by 8%.
- Unlocked at Assassination rank 42.
- Update 6: This ability allows you to fire a spectral projectile at your target, dealing magic damage.
- Update 2: Incapacitate: This ability now increases heavy attack damage.
- Update 3: Incapacitate: This ability now has a visual effect when an enemy is immobilized.
- Update 6: This ability has replaced Haste in the Assassination tree. Any experience gained in Haste will now apply to Grim Focus.
- Update 6: When Grim Focus is activated, all weapon attacks will do additional damage for 20 seconds. Using light attacks or heavy attacks while the effect is active will grant a charge. When you gain eight charges, Grim Focus changes to Assassin's Will.
- Update 7: The bow on Assassin's Will is now easier to see in first-person view, and can now be activated after 4 light attacks instead of 7.
- Update 8: Using a number of abilities, including this one, will now cause your weapon to unsheathe.
- Update 9: Fixed an issue where the weapon visual effects from abilities such as Grim Focus, Siphoning Strikes, and Expert Hunter could get visually detached from the weapon.