Harald is a frost giant who took Sam al-Abbas and Magnus Chase fishing for the world serpent. Jormungand.
Magnus Chase and the Gods of Asgard
The Sword of Summer
Magnus and his friends encountered Harald at the pier and requested that he take them fishing. After being paid in Red Gold by Sam, Harald allowed her and Magnus to come but not Hearth and Blitz. They set sail to Jotunheim and threw in the bait. Before long they got a bite. Harald pleaded with Sam and Magnus to cut the line but they did not. Jormungand then surfaced and then Ran appeared soon after. After the demigods retrieved the sword Harald set sail for shore. Sam made sure he left them in Midgard rather than Jotunheim.