The story of Gilles de Rais is also quite disturbing. He was a French nobleman who was later found to have committed heinous crimes including sexual abuse and murder of children. His actions were truly 'messed up' and his case is a very dark part of history.
In some medieval tales, there were accounts of nobles misusing their power for sexual exploitation. For example, some lords would force themselves on peasant women. These stories show the dark side of power and sexuality in that era.