Complex sentence: After defeating the Arch Lich Deimos, the heroes continued on their journey through the Broken Lands of Glantri after realising that Deimos is only part of a greater evil plan, and he was in fact being used by a mysterious sorceress named Synn.
Split into simpler sentences: After defeating the Arch Lich Deimos, the heroes continued on their journey through the Broken Lands of Glantri after realising that Deimos is only part of a greater evil plan. Deimos was in fact being used by a mysterious sorceress named Synn.