Martyrizer is an uncommon term that can mean someone who persecutes or torments others. If you're looking for synonyms that more precisely describe this kind of behavior, there are plenty of options available. Some suitable alternatives include torturer, tyrant, oppressor, bully, abuser, and intimidator. Each of these words connotes a different type of cruelty or abuse, ranging from physical harm to psychological manipulation. Depending on the context of your writing, one of these synonyms may be more appropriate than others. Ultimately, using synonyms like these can help you to more accurately convey the nature of the perpetrator's actions.