Grundroth was a member of Laufey's army who fought with Thor, Loki, Sif and the Warriors Three, as they invaded Jotunheim. However, he was defeated by a single strike from Mjølnir, which sent him flying against a frozen mountain. He then rose to fight Hogun of the Warriors Three with twin Ice Daggers.
Mission at Asgard
He was later one of the Frost Giants that was brought to Asgard, by Loki, along with Laufey to assassinate Odin. Grundroth was assigned to guard the Bifrost Bridge and an incapacitated Heimdall, who was earlier frozen by Loki. However, Heimdall was eventually able to break free of his icy prison and decapitated Grundroth, just as he was about to strike.
Powers and Abilities
Frost Giant Physiology: As part of a race of humanoid giants that live on Jotunheim, Grundoth's Frost Giant features had granted him superhuman abilities.
- Superhuman Strength: Grundroth has strength much greater than that of a human being.
- Superhuman Durability: With his Frost Giant physiology, Grundroth managed to survive a strike from Mjølnir.
- Cold Immunity: Grundroth lived his life in Jotunheim, a realm that is cold enough to kill a human, without being harmed.
- Combatant: Using his twin Ice Daggers, Grundroth could easily fight Thor and the Warriors Three.
- Heimdall † - Attempted Victim and Killer
- Warriors Three
- Loki †