Complex sentence: Initially he was intended to be a temporary replacement for Kenny Morris, who had left the band two days into a tour, but he remained with the group, from the album "Kaleidoscope", until they split up.
Split into simpler sentences: Initially he was intended to only be a temporary replacement for Kenny Morris, who had left the band two days into a tour. However he remained with the group, from the album "Kaleidoscope", until they eventually split up.