The intention is to keep Critical Damage at the 125% maximum. If you find that you're exceeding that in your group you may want to make adjustments to increase your Weapon and Spell Damage.
Maybe switch from The Thief to The Warrior.
- Pre-buff: Cast Dark Shade and Siphoning Attacks before pulling.
- Opener: Drop Stampede, Carve, and Twisting Path on the back bar.
- Front-Bar Loop: Cast Deadly Cloak, fire Merciless Resolve when at 5 stacks, and weave Surprise Attack light attacks.
- Execute Phase (< 25% Boss Health): Stop using Surprise Attack and swap entirely to spamming Killer's Blade while keeping Deadly Cloak and back-bar DoTs refreshed.