In the early 2000s, she and Arne Sandvoll founded the electronic music duo Ullan Gensa, which released tracks on the Internet and performed a few concerts in Norway.

[1] The multi-instrumentalist Einar Selvik, who began to develop the eclectic ambient music group Wardruna in 2002,[2] had seen one of Ullan Gensa's shows and approached Hella.

[1] Selvik said he wanted the particular energy of Hella's singing to feature in Wardruna's music, which revolves around brooding moods, historical instruments and runes.

Hella's original plan was to make it an album with only her vocals, but she became bored with the idea and brought in a few collaborators, including producer and former-Enslaved keyboardist Herbrand Larsen, Wardruna member Eilif Gundersen and metal singer Kristian "Gaahl" Espedal.

[6][7] Laura McCarthy of Distorted Sound wrote that the album combines groundedness in the natural world with an appeal to the mystical, and a will to be both in the past and the future.

[9] In 2024, Hella launched the group Whispering Void, whose other members are Gaahl on vocals, Ronny "Valgard" Stavestrand on guitar and Iver Sandøy on drums and bass.