Complex sentence: He is an old evil spirit who fell in love with Jenny when she opened the closet, which the Shadow Men had been captured in by her grandfather, and watched Jenny for countless years making sure that nothing bad ever happened to her.
Split into simpler sentences: He is an old evil spirit who fell in love with Jenny when she opened the closet, which the Shadow Men had been captured in by her grandfather. He watched Jenny for countless years making sure that nothing bad ever happened to her.