Thunderclap

Summary
For 8...18 seconds, the next time target foe is struck for lightning damage, that foe and adjacent foes are knocked down, and you lose 15...9 energy or Thunderclap ends. This is an elite skill.

Acquisition

 * Thunderhead Keep: Signet of Capture, Chrysos The Magnetic
 * Ring of Fire: Signet of Capture, Maida the Ill Tempered
 * Iron Mines of Moladune: Signet of Capture, Kratos the Foul
 * Iron Mines of Moladune: Signet of Capture, The Inquisitor