“Look out, everybody, things are about to get awesome!”
As part of her research into studying the minds of psychos, Tannis discovers that every psycho shares the same single thought powerful enough to shatter their minds: Vaulthalla. To seek out the answers of what lies within Vaulthalla for themselves, Tannis sends the Vault Hunters to a physical representation of the mind of the Crimson Raiders' resident psycho Krieg, created in an area of space she deems "psychically-neutral". Using a modified drop pod designed by Tannis with a neural digi-matrix interface, the Vault Hunters journey into Krieg's Mind, seeking to open Vaulthalla and to uncover the mysteries within.
Inside his mind at an area called The Psychoscape, the Vault Hunters meet two versions of Krieg; the "Sane Krieg" and the "Psycho Krieg", both of who share a bitter disdain for the other. Sane Krieg explains to the Vault Hunters that Psycho Krieg locked the path to Vaulthalla long ago, and that they would be willing to assist the Vault Hunters in tracking down the pieces of the statue needed to open it through various past memories of theirs in exchange for extracting Sane Krieg from the twisted mindscape of his psycho self. The combined group soon venture through three different areas of Krieg's Mind, witnessing twisted versions of Krieg's memories before uncovering each of the three statue pieces. Assembling the pieces back at The Psychoscape, the path to Vaulthalla is opened, and the group soon traverse inside.
Within Vaulthalla, the group encounter the guardian of the realm, Psychoreaver, and engage him in battle. Upon killing him, they discover that Vaulthalla was collapsing, and Sane Krieg orders the Vault Hunters to enter an area of Vaulthalla called the "Trove of the Despoiler" to loot whatever they wanted in a limited time. Upon exiting the area, the Vault Hunters meet with the two Kriegs, who reconcile with one another; when offered the opportunity to finally leave his psycho self's mind by Tannis, Sane Krieg declines, having finally realized that Psycho Krieg was in reality shielding him from Psychoreaver's madness the whole time. For the first time, the two Kriegs work together to create a peaceful landscape consisting of a home with their deceased love interest Maya, and finally unite as one being.
After the bittersweet moment, Tannis tells the Vault Hunters that they can now venture into Krieg's Mind whenever they'd like, jokingly remarking that Krieg "wouldn't mind".
- Krieg's Mind is classified as an "Unstable Consciousness".