Under Desert Sands, Part 3 - S1.E29

Gale defends Haru from the mole monster that was about to give a surprise attack from underground, then Gale runs off to the Tower. King is standing at the entrance, and meets Gale head-on, showing off one of his Shadow Stones which can release energy that disintegrates anything it comes in contact with. It turns out that King's first name is also Gale (full name: Gale Raregroove), and Haru realizes that his father is not the enemy.