Complex sentence: He then brings Adelle home to her mother where they say that Paul's victory was the will of God which Adelle agrees, however whilst Paul and her mother look away Adelle's eyes turn black indicating that that she has being possessed by a demon.
Split into simpler sentences: He then brings Adelle home to her mother where they say that Paul's victory was the will of God, something to which Adelle agrees. However, whilst Paul and Adelle's mother look away, her eyes turn black, indicating that that she has been possessed by a demon.