控制者 is the standard agent-noun form:
控制 (to control) +
者 (-er/-or, person who does the action). Common in legal, corporate, and technical contexts - particularly in data protection law where
数据控制者 /
个人信息控制者 corresponds to GDPR's "data controller". For people who control by force (rulers, dictators),
统治者 is more idiomatic.
