the.com/nemesis

means A longtime rival or arch-opponent whose talents are perfectly, infuriatingly matched against your own.

from From Nemesis, the Greek goddess of divine retribution who punished hubris and excess — her name comes from the Greek 'nemein,' meaning 'to give what is due.' For centuries the word meant fated, deserved downfall, the cosmic payback for pride. Only later did it soften into its modern sense of a personal rival — someone who feels less like justice from the heavens and more like the universe's way of keeping you humble.