Universe
Marvel Universe

Real Name
Gruenhilda

Aliases
Hilda Grune, "Grunny"

Identity
Secret

Citizenship
Asgard

Place of Birth
Asgard

First Appearance
Thunderstrike #1 (2011)

Origin
Unrevealed

Gruenhilda was tasked to instruct Kevin Masterson how to properly wield the Thunderstrike mace by the goddesses Sif and Hecara after Steve Rogers gave it to the boy. Kevin's father was owed a debt of gratitude by the Asgardians for his courage and honor by first merging with, then briefly replacing Thor after the thunder god was banished. When Thor returned, Odin created the Thunderstrike mace, gave it to Kevin's father, and he became the hero Thunderstrike whose final act was to sacrifice himself to save the world. Now that the mantle had passed from father to son, the debt could be repaid.

Gruenhilda traveled to Earth and found Kevin just as he was attacked by the Spartans strike force of the sports mogul Adam Mann. They were trying to secure the mace for their employer who sought to steal its power. Although a valiant warrior, Gruenhilda could not prevent them from taking the mace, but she did save Kevin's life and the life of his adoptive-father, Bobby Steele. She stayed with Kevin, adopting the civilian identity Hilda Grune, eventually infiltrating Mann's home to retrieve the mace, and led the attack against Mangog after the demon was summoned through Mann's Mysticator. Gruenhilda was not powerful enough to defeat the beast, but she did save Kevin from being devoured by it. She then fought side-by-side with the Avengers to prevent Mangog from destroying New York City and helped Thunderstrike and Thor exile the creature elsewhere. Afterward, Gruenhilda remained by Kevin's side even as he challenged the Rhino to a rematch.