Seer Skahi:
Follow him to get to the truth. You must find the Resonance Amulet.
The power of the king that you seek was created by the gods, but stolen by devils.
Find the Archon of Halisha inside the Four Sepulchers at the Human Imperial Tomb!
If entering is too difficult, go to the Shrine of Loyalty and fight Halisha's minions! He'll show up if you kill enough of them.
Defeat him and get the Resonance Amulet!