Hundred Blades

Acquisition
Signet of Capture:
 * Prophecies
 * Spoiler-related boss, see below (Hell's Precipice)
 * Factions
 * Warrior's Construct (Sunjiang District (Mission))
 * Warrior's Construct (Sunjiang District (Explorable))
 * Nightfall
 * Blade of Corruption (Nightfallen Jahai, during Breaking the Broken)
 * Reaper of Agony (Depths of Madness)
 * Guild Wars Eye of the North
 * Justiciar Thommis (Slavers' Exile,Justiciar Thommis (Dungeon))

Trivia

 * This skill is used by Prince Rurik and is one of the few elite skills used in pre-Searing.

Acquisition
Signet of Capture:
 * Prophecies
 * Undead Prince Rurik (Hell's Precipice)