Complex sentence: Raistlin Majere attempts to destroy Takhisis and assume her role as head god of evil, and succeeds in one timeline, but destroys the world of Krynn in the ensuing magical battle.
Split into simpler sentences: Raistlin Majere attempts to destroy Takhisis and assume her role as head god of evil. He succeeds in one timeline, but destroys the world of Krynn in the ensuing magical battle.