Complex sentence: The next album, "Battles in the North" was also recorded by only Abbath and Demonaz as Grim had been asked to leave as they felt he could not help them move their music forward.
Split into simpler sentences: The next album, "Battles in the North" was recorded by only Abbath and Demonaz. They had asked Grim to leave the band, as they felt he could not help them move their music forward.