Merciless cut
rogue attack 19
Melee weapon
Requirement: wielding a light blade.
Effect: Before the attack, you shift your speed.
Target: one creature
Attack: Dexterity vs. Reflex
Hit: "4[W] + Dexterity modifier damage, and ongoing 10 damage (save ends)."[MP2:68]
Merciless cut is a daily power available to rogues at 19th level.