Norberg on bass, Asgeir Mickelson on drums, and guest vocals from Mikael Åkerfeldt (of Opeth) on the track "Unhealer". In March 2009, Tveitan performed some of his solo material live for the first time, in a one-off performance opening for Opeth in Norway. He has since made many festival appearances, playing a mix of solo material and Emperor covers. Fellow Norwegians Leprous have served as his backing band. Grimen, the only album by side project 'Hardingrock' was released the same year. Tveitan released his third solo album, After, in January 2010. Lars K. Nordberg and Asgeir Mickelson once again contributed bass and drums, respectively, with Jørgen Munkeby (of Shining) playing saxophone on several tracks as well. Later that year, in October, a Mnemosyne web update confirmed that Ihsahn had already begun writing for a fourth solo album, and was also focusing on upgrading his studio at home. 2011–2013: Bilateral, Eremita, and Das Seelenbrechen 2011 was a busy year for Tveitan. Aside from making his solo debut in the US at the annual ProgPower USA metal festival in Atlanta, Georgia, he also performed as a guest on two records, co-produced the album Bilateral with his wife, and continued to work on his fourth solo album. Collaborators once again included Jørgen Munkeby and Devin Townsend, who in a November 2011 interview mentioned that he was "singing a song for Ihsahn's new thing", but added that he could not elaborate any more at that point in time. In 2012, Tveitan released his fourth studio solo album, Eremita. Das Seelenbrechen was released on 21 October 2013. It was recorded in Juke Joint Studio and Tveitan's own Mnemosyne Studio. 2016–2018: Arktis and Àmr In April 2016, Tveitan released his sixth studio album, Arktis, on Candlelight Records. The album was mixed and mastered by Jens Bogren. The album cover features a photograph of Fridtjof Nansen, whose 1896 mission to the North Pole fits with the lyrical atmosphere of the album. They also share their birthday of 10 October. In 2018, Tveitan released Àmr, his seventh studio album. The title of the album is an old Norse word for "loathsome" or "black" and reflects the introspective nature of the songs. Tveitan added that the word Àmr, could also mean "rust red" and that the concept of a "room without walls" was a prevalent metaphor when working on the album. In comparison to previous albums, Àmr also features