Nezuko Is The Final Key To Defeating Muzan, Not The Sun
In Demon Slayer - Swordsmith Village Arc, Nezuko conquering the sun was the biggest moment of the last arc. For the first time ever, a demon walked in sunlight. Muzan has wanted this for a thousand years.
But a new fan theory argues that Muzan completely misunderstood his own goal.
Fans think Nezuko didn't just conquer the sun — she became immune because she is evolving past being a demon.
Remember, Nezuko never eats humans. She sleeps to regain energy instead of feeding, which no other demon does. Tamayo even said Nezuko's physiology is completely unique.
The theory goes: Muzan was created by the medicine that was supposed to let him walk in the sun. The Blue Spider Lily was supposed to make him transcend death. What if the Blue Spider Lily doesn't make a demon sun-proof, it makes a demon human again but with demon strengths?
Nezuko is slowly reverting. She's regaining her speech, her emotions, her memories. Conquering the sun isn't her final demon power-up — it's the first sign she's becoming a new species entirely. A perfect being that is neither human nor demon.
And that's why Muzan will never achieve it by eating her. He can't evolve because he keeps consuming humans, while Nezuko evolved precisely because she refused to.