nemesis

plural nemeses

1. An enemy, especially an archenemy.

   Batman is in constant conflict with his nemesis, The Joker.

   4 more examples

   The roofer stayed in touch, committed to the downfall of his nemesis, Mikey. One week after his initial phone call, we were on our way to raid Mikey's trite home armed with a federal search warrant. There were six of us.

   2001 June 1, Mark Hunter, The Powder, Their Paper and Pools of Blood, iUniverse, →ISBN, page 186

   They were different in many ways but what was it about opposites attracting... […] She was his opposite, but not his nemesis, and they worked well together. She hoped he liked working with her.

   2009 April 7, Paul Daffinrud, The Janitor Solves a Murder, iUniverse, →ISBN, page 16

   Jack took many hits to his body from his nemesis, but to his surprise he barely felt it. Jack's nemesis looked at him with anger in his eyes, clinching his fist to throw the next blow and without hesitation he threw another punch[…]

   2020 January 30, Prince Edderson Charlton Jr, The 8 Wundas of the World: Volume One, Lulu Press, Inc, →ISBN, page 4

   Along the way, they meet Master Wong, who teaches them kung fu and imparts nuggets of Chinese philosophy, knowledge and training that they eventually use to defeat their nemesis and save their village.

   2021 March 31, Melissa Chen, “Opinion ‘Kung Fu Cavemen’ isn’t racist — just the victim of moral panic by a self-righteous few”, in New York Post

2. A person or character who specifically brings about the downfall of another person or character, as an agent of that character's fate or destiny, especially within a narrative.
3. The personification of the "fatal flaw" of a dramatic hero in the style of Greek tragedy.
4. Polar opposite, especially of a literary character.

   1 more example

   “And then, while he's devouring you with his stare, thinking about how much he wants to lick you up, along comes his antithesis, his polar opposite, his nemesis for want of a better word—” “Nemesis?” I interrupted, eyebrows journeying up my forehead. “—who swoops you off your feet and away from him,” Heather continued, ignoring my incredulous expression.

   2020 January 13, Lexxie Couper, Unconditional, Lexxie Couper, →ISBN

5. The principle of retributive justice.
6. formalsingularusuallyA punishment or defeat that is deserved and cannot be avoided; (an instance of) retribution.

   Even Nathan's close associates, who are not yet ready to declare themselves his enemies, accept that his engineered downfall will be his nemesis for harbouring ambitions beyond his status, and do nothing to alert him to the situation[…]

   2021 November 8, Linzy Erika Dickinson, Theatre in Balzac's La Comedie humaine, BRILL, →ISBN, page 90

1. Greekhuman sciencesThe goddess of divine retribution.
2. astronomy128 Nemesis, a main belt asteroid.
3. astronomyA hypothetical star postulated to be orbiting the Sun to explain a perceived cycle of mass extinctions in the geological record.