retaliator

/rɪˈtæliˌeɪtər/
noun
  1. A person or thing that takes revenge or responds to an injury or wrong.
    • The company's legal team acted as a retaliator against the false accusations.
    • The retaliator struck back after the insult.
    • In the story, the hero is a reluctant retaliator who only fights when provoked.
Synonyms