Complex sentence: Nights is a Nightmaren created by Wizeman to steal Red Ideya; however, Nights betrays Wizeman and is sealed in the Ideya Palace until Elliot or Claris Dualizes with him to get the Ideya back.
Split into simpler sentences: Nights is a Nightmaren created by Wizeman to steal Red Ideya. In the story, Nights betrays Wizeman and is sealed in the Ideya Palace until Elliot or Claris Dualizes with him to get the Ideya back.