Complex sentence: He is also the guitarist for the Swedish progressive rock group Kaipa and joined the American melodic death metal band The Absence as a permanent member in January 2013, having earlier contributed a guest solo for their 2007 album "Riders of the Plague".
Split into simpler sentences: He is also the guitarist for the Swedish progressive rock group Kaipa and, since January 2013, one of the guitarists of American melodic death metal band The Absence. He had contributed a guest solo before he joined for their 2007 album "Riders of the Plague".