"Shields Up!"

Acquisition
Skill quests Skill trainers Signet of Capture
 * Prophecies
 * The Misplaced Sword (Heroes' Audience)
 * Prophecies
 * Bartoch (Droknar's Forge)
 * Dakk (Ember Light Camp)
 * Factions
 * Michiko (Kaineng Center)
 * Ziinyingmao Kaga (Dragon's Throat)
 * Akane (Senji's Corner)
 * Nightfall
 * Zendeht (Gate of Torment)
 * Prophecies
 * Thorgrim Beastlasher (Iron Horse Mine, only during Stone Summit Beastmasters)

Trivia

 * "Shields Up!" is a reference to the famous quote from the Star Trek franchise.