Kūro the Cautious is a leprechaun spy and a former member of the covert organization known as the Obsidian Eyes. He is a young man with short gray hair and turquoise or blue-green eyes, typically dressed in a beret, coat, and turtleneck. His cautious and serious demeanor reflects his background in intelligence work; he is calm, collected, and carefully observes situations before acting. Having left the Obsidian Eyes, he longs for a peaceful life and becomes reluctantly drawn into the larger power struggle within the nation of Aureatia. He is accompanied by his constant partner, the tiny homunculus named Cuneigh the Wanderer, and the two work together as a team. Kūro possesses a unique perceptual ability that allows him to sense heat and magnetic fields, making him an exceptionally effective spy and tracker. In the second season of the anime, he takes on the role of hunting down a traitor, demonstrating his investigative skills and his willingness to engage in dangerous missions despite his preference for safety. His development centers on navigating the tension between his desire for tranquility and the demands placed on him by the turbulent world of competing shura.