Of all the heroes to call themselves Defenders, Valkyrie was the most dedicated to the team. Yet she joined their ranks in the most roundabout way.
Realizing the malevolent intent of a secret ceremony, Barbara Norriss sacrificed herself into another dimension to spare an innocent man that fate. That man was Bruce Banner (The Incredible Hulk #126). Hulk and his non-teammates later rescued Norriss from her otherworldly imprisonment. But they were saddened to find that the horrors she experienced there, in the clutches of the Nameless One, had driven Norriss mad (Defenders #3).
Immediately afterward, the Defenders encountered the unscrupulous Enchantress, who had magically enslaved the Black Knight. The Asgardian sorceress placed the spirit of a valkyrie into the body of Norriss, expecting to control her as well. Yet the reborn valkyrie proved to have a mind of her own. The Enchantress fled, turning Black Knight to stone as she left (#4; Dr. Strange reversed the spell in #11).
Valkyrie assumed custody of Black Knight's winged horse, Aragorn, and sought membership into the Defenders.
- Namor: One minute now! The Defenders have no "members." We have only fought together for common causes. This is not the Avengers!
- Dr. Strange: Further--with all due modesty, we are three of the most powerful people in the world. What could we possibly need you for?
Valkyrie was the only early Defender to stay with the team through the creation of the New Defenders (#125) and the end of the series (#152).