a sadist
Examples
Exploitation and manipulation produce boredom and triviality; they cripple man, and all factors that make man into a psychic cripple turn him also into a sadist or a destroyer.
She had opened a door... and now she was walking with demons. And at the end of her travels, she would have her revenge... Pain had made a sadist of her.
A person who feels pleasure in producing pain in someone else in a sexual relationship is also capable of enjoying as pleasure any pain which he may himself derive from sexual relations. A sadist is always at the same time a masochist.
[Spike] is a sadist and he is never happier than when he is hurting people or killing people, but he is truly, sincerely, deeply in love with Drusilla.
If there is only one Creator who made the tiger and the lamb, the cheetah and the gazelle, what is He playing at? Is he a sadist who enjoys spectator blood sports? ... Is He manoeuvring to maximise David Attenborough's television ratings?