The Beginning of Sorrow

Tanjiro ends up smelling the blood that's coming from his house while at old man Saburo's house and sprinted up the mountain. Tanjiro gets there and saves Nezuko from becoming a demon, when he wakes up he finds that Nezuko woke up but so did another sibling (which one is it???) and were heading down the mountain to get help, but two demons attack them in an attempt to finish the job, but all the hashira were sitting in the trees. Who saved the two siblings who were frantically trying to save the family they could? Who called the Hashira to get here??? If Tanjiro has super smell what do the other siblings have???