How did Nezuko conquer the sun?

Question

So, I just completed the Demon Slayer anime until its current season (never read the manga). I am very confused at the fact that Nezuko was able to conquer the sun, but Muzan can't.

Tamayo states that Nezuko is prioritising something else over intelligence and in the future will conquer the sun.

But if Nezuko can potentially prioritise her mutation for sun protection, why can't Muzan, who is the original, has been alive longer, has much more power, control, and knowledge, has done a lot of experiments, etc.? Is there any special ability with Nezuko? Is this explained later? I am okay with spoilers.

Answer 1

It was revealed by the second official databook of Kimetsu no Yaiba (Demon slayer) that Nezuko consumed the Blue spider lily when she was little. The Blue spider lily, when consumed, has the ability to let demons be immune to sunlight, and as a result was actively sought by demon king Kibutsuji Muzan. However, since the Blue Spider Lilies are very rare, and blossoms only very occasionally and during the day, Muzan was never able to obtain it. It is possible that Kei (Tanjiro and Nezuko's mother) and Tanjuro (Tanjiro and Nezuko's father) had some knowledge about the Blue Spider Lily and its powers and managed to find it (they're humans, so they could search for it during the day). Another proof to support the claim is that in the anime, in her letter to Tanjiro at the end of Season 3 Swordsmen Village Arc, Tamayo stated that she found traces of "blue" in Nezuko's blood samples that Tanjiro gave her. This "blue" in Nezuko's blood may well have been traces of the Blue Spider Lily. If Nezuko had in fact consumed the lily, then her immunity to sunlight is reasonable and quite probable.

For more, see did Nezuko consume the blue spider lily