Possible Clues:

• Emma Peel, e.g.
• One doing harm to get their own back
• Steed or Mrs. Peel
• Eye-for-an-eye seeker
• Steed of British TV
• One gets even a priest beginning to gall a monarch
• Ant-Man, Iron Man, Wasp or Thor, in Marvel Comics
• He seeks satisfaction or retribution
• Hamlet, for one
• Someone seeking to settle a score