Vow of Silence

Acquisition
Signet of Capture:
 * Nightfall
 * Chundu the Meek (Gates of Desolation (Mission))
 * Vahlen the Silent (The Sulfurous Wastes)
 * Water Lord (The Hidden City of Ahdashim - only during the Gift of the Djinn Quest)

Related Skills

 * Spell Breaker (Elite)
 * Shadow Form (Elite)
 * Obsidian Flesh (Elite)
 * Spell Shield