Mark-Ironer Youkai
A powerful youkai which was sealed in Oosugi. He left a curse mark on Natsume that would kill him in five days. Hinoe helped Natsume to summon shiki that would protect him against this youkai.
It was Misuzu who had lured Natsume to this youkai. He was testing if Natsume is worthy person to hold his name in the Book of Friends.