Hamstring

Acquisition
Skill Quests: Skill Trainers: Hero Skill Trainers:
 * Prophecies
 * Caravan in Trouble (Eastern Frontier)
 * Prophecies
 * Captain Osric (Yak's Bend)
 * Dakk (Ember Light Camp)
 * Factions
 * All Factions skill trainers (except Zhao Di and Xu Fengxia)
 * Nightfall
 * Godaj (Lair of the Forgotten)

Trivia

 * This skill has a unique attack animation. The character starts to perform a regular slash, but brings the sword the equivalent of about 8 inches lower, then performs a swift right-to-left slash at this lowered height.  Presumably, this would be striking the opponent's legs, although it still works against things which lack them, and the attack hits somewhat higher than a proper hamstring would.