Misuzu is a powerful upper-class youkai who appears in the animated film Natsume’s Book of Friends: The Stone Waker and the Strange Visitor. He is a water horse ayakashi with black skin and the head of a horse, typically wearing a lavender kimono, with pierced ears adorned by golden rings and small bells. As a swamp guardian, he commands frogs and other swamp creatures, and he leads many followers. Misuzu is the only youkai whose name remains in the Book of Friends, originally taken by Reiko Natsume, and later he voluntarily entrusts it to her grandson, Takashi Natsume, after testing Natsume’s character. His personality is initially condescending and deceptive; he tends to look down on weaker youkai and humans and often speaks with hidden motives. However, he also proves to be protective of his servants and willing to help his friends. Over time, he develops a respectful bond with Natsume, whom he addresses as “my lord,” and becomes a loyal ally. In the film’s segment The Strange Visitor, Misuzu appears in human form for the first time, taking on a tall, androgynous appearance with wavy purple hair and a bell on one ear, wearing a suit. He visits Natsume’s friend Tanuma repeatedly because a fellow youkai named Sasame has possessed Tanuma, and Misuzu waits for Sasame to grow bored and leave. His motivations often revolve around testing others’ worthiness and protecting those he considers important, and he acts as a recurring ally who can be called upon through the Book of Friends. Notable abilities include shape-shifting into a human guise, flight, immense physical strength, and the power to command frogs. He also displays a playful side, such as eagerly joining games like shadow tag, and is deeply involved in the series’ exploration of the relationships between humans and youkai.