Harshnag the Grim was a frost giant played by guest star Joe Hills. The Wafflecrew went to Harshnag's ice tower to ask the frost giant if he would help investigate Ironslag. He agreed to go with them. Harshnag helped the Wafflecrew attack the yakfolk settlement. During the assault, Harshnag fell off a cliff fighting an earth elemental and is presumed dead. Kuharik later said that while out in the area where Harshnag fell, he found the frost giant's axe, but no corpse.
Harshnag is an NPC from the Storm King's Thunder adventure. He originally appeared in a number of old D&D supplements, including Heroes' Lorebook and City of Splendors: Waterdeep.
Episode 39 - Fortune Favors the Cold
Episode 40 - Big Yak Attack