WARNING: The following contains spoilers for King in Black: Return of the Valkyries #2 by Jason Aaron, Torunn Grønbekk, Nina Vakueva, Tamra Bonvillain, & VC's Joe Sabino, on sale now.
When the symbiote god Knull landed on Earth, he almost immediately knocked out the defensive line planned out by the Avengers. Since the King in Black took over many of the top heroes, including Captain America and Storm, the remaining good guys have been searching everywhere for allies. This has been bringing many characters, both good and bad, out of the woodwork to join the ranks against Knull.
Jane Foster, in her current role as a Valkyrie, has been assembling a team of former Valkyries to assist in the fight. She stumbled across a former Valkyrie that was lost in a type of purgatory. After saving her, Jane journeyed to Asgard to find Hildegarde, one of the first and greatest Valkyries. Lady Sif, the All-Seer, informed Jane that Hildegarde was already on Earth because a war of heroes and gods against unspeakable monsters with a slim chance of survival is "very much her thing."
Of all people, Sif would understand the warrior Hildegarde. The two first met in Thor #195, by Gerry Conway and John Buscema, published in 1972. During this time in the comics Sif was a lady of Asgard who only awaited her wedding, not the thrill of battle. Odin charged Hildegarde with escorting Sif to another world, protecting her while Thor was on a dangerous quest. Hildegarde valiantly took on knights and monsters that tried to harm them, never wavering or backing down. When overpowered, Hildegarde told Sif to grab a weapon and pull her weight, awakening a battle spirit in Sif that stayed with her and later turned her into a formidable warrior. Hildegarde's indomitable spirit is contagious to all of those around her, even once proper ladies like Sif.
The two women eventually reunited with Thor. Hildegarde was neither intimidated nor impressed, by Thor or the Warriors Three -- Thor's closest allies. She held her own in battle in front of the seasoned fighters and claimed her own place alongside the Warriors Three.
Yet it is more than her prowess with a sword or ax that she brings to the table, Hildegarde is as witty as the rest of the heroes. When fighting alongside Spider-Man she referred to him as Spider-Boy. Of course he corrected that his name was "man" and not "boy" but she quipped back that man "must have a different meaning on Midgard." One of her most memorable moments came in Aaron, Torunn Grobekk, and Ramon Rosanas' Valkyrie: Jane Foster #10 when she told an angry Tyr that he may be the god of war but she was the "goddess of not giving a damn."
It makes perfect sense that Jane would want Hildegarde to join the ranks against Knull so she followed her to Earth. Arriving, Jane found another former Valkyrie -- Dani Moonstar -- trying to take down one of Knull's dragons. The two warriors turn to face the dragon when a third figure leapt in and attacked the dragon -- Hildegarde. Joining her companions, she looked at the dragon and asked if they should finish off the "wee" thing. Although Hildegarde may not be highlighted as much as other characters, she is someone who would be very helpful in a fight, never tiring, and keeping everyone on their toes. She keeps the drive going against enemies, no matter how many times she's been hit, and has proven on more than one occasion to be a warrior among warriors.