why can nezuko walk in the sun

Nezuko Kamado can walk in the sun in Demon Slayer because of unique factors related to her blood and lineage. One major explanation is that Nezuko's blood contains the Blue Spider Lily, a flower that nullifies demons' usual weakness to sunlight. This flower grew near her home and Nezuko likely consumed it, causing rapid mutation in her blood that allowed her to overcome sunlight vulnerability. Another theory is that she comes from a Sun Breathing lineage, as her family practiced Sun Breathing — a powerful technique linked to the sun — which may give her immunity. Furthermore, Nezuko never consumes human blood, which might contribute to her unique physiology and strength against sunlight. These factors combined make her an exceptional demon capable of surviving in daylight, which is normally fatal for demons.