Nyanko-sensei, also known as Madara, is a powerful youkai that resembles a maneki-neko, or lucky cat. He serves as protagonist Takashi Natsume’s bodyguard and guide in the Natsume’s Book of Friends series under the condition that when Natsume passes away, Nyanko-sensei will receive the titular Book of Friends, a collection of contracts made with various youkai started by Natsume’s late grandmother, Reiko Natsume.
Despite his sweet appearance, Nyanko uses the maneki-neko form as a disguise. He is actually a giant and incredibly powerful, taking the form of a wolf-like youkai. He is also both playful and wise, constantly making jokes, and although he tries to hide it, he is very caring, making him a character fans have fallen in love with.