Rubin has red tentacles and a red shell with a flame pattern on it. He often gets furiously angry. When he does, he grows even more red than usual, and he screams and complains at whoever is around him! Together with the firefly and the bat, he decides to embark upon a journey. With their help, he manages to overcome his anger, and cope. And, of course, Luman, who is a member of the Bravyan council at the castle, is on his side, too. During his journey, Rubin looks at the source of the north river, a natural statue of a horse, and realizes that when he gets angry, he’s like a wild horse, galloping and kicking aimlessly. He strives to be a horse who can gallop toward his goals without distractions. Rubin discovers that light is the source of his power, and he is able to deal superbly well with whatever he encounters.