Complex sentence: A demonic spirit who was defeated and imprisoned in a cave many centuries before the events of the story, the Evil Witch of the Dark was accidentally released by DG and Azkadellia when they were children and took possession of Azkadellia.
Split into simpler sentences: A demonic spirit who was defeated and imprisoned in a cave many centuries before the events of the story. She is accidentally released by DG and Azkadellia when they were children and took possession of Azkadellia.