All demons gain a lot of muscle mass once they are turned, due to this you gain a +3 to your strength score

One of Nezuko Kamado's abilities is to change her size so she can fit in a basket or a box, she never really gets bigger except when she is initially turning. You can change your size from medium to small and vice-versa at will

Many times in the anime, demons are shown to regenerate from small scratches to very large wounds such as getting their heads blown off Nezuko does this a bit differently, by sleeping which is why you have to take a long rest instead of a short one. after taking a long rest you may regenerate 1D12 + CON as a free action or a reaction, you may use this ability 4 times per short rest

In the fight with Rui, Nezuko finds her blood demon art (i.e. Exploding blood) she ignites her blood to catch Tanjiro's blade afire which assists in cutting off Rui's head. when you use Exploding blood you take 1D6 + 3 damage and shoot out a 15-foot cone of flames which do 1D10 + 3 damage to each creature/player inside the cone, if you roll critical damage then roll another 1D10, if that rolls critical then roll another 1D10. Continue until you don't roll critical damage (the damage increases by 1D10 at levels, 5, 8, 11, and 14)

When Nezuko is first exposed to blood in the anime she pauses, resisting the urge to feed on the flesh of a human, this happens a few times but she gets better at resisting each time. When you are exposed to human blood for the first time in a fight you are stunned, your mouth watering for 1 round before you can join the fight  again (happens 1 time per fight)