Kuromaru, eldest son of the Karasu Tengu and a member of the Sanba Garasu triplets, is a figure of serious duty from the *Nurarihyon no Mago* series. At 118 yōkai years—the equivalent of 18 human years—he was born on August 31. His human form possesses black hair and red eyes, standing 173 cm tall and weighing 65 kg. When transformed into his yōkai state, he adopts an anthropomorphic, bird-like appearance with a black body, retaining the dark tan tokin on his forehead. He is typically clad in samurai-like armor and wields a staff or sword. His personality is marked by a rigid adherence to rules and a deep-seated seriousness, traits inherited from his father. As the leader of his siblings, he exhibits a strong sense of responsibility and unwavering loyalty to Rikuo Nura, following orders without hesitation. This dedication often leads him to report incidents directly to his father, even when it complicates matters for others, revealing an inflexible commitment to protocol. He holds a particular contempt for arrogance, a trait evident in his dealings with figures like Inuhōō. Kuromaru’s involvement is pivotal across multiple story arcs. He first appears alongside his brothers to deliver reports and participate in rescue operations, such as saving the Kiyojūji Paranormal Investigation Squad and later aiding in the search for Rikuo. During the Shikoku conflict, he and his siblings investigate attacks, assist in locating Sodemogi-sama, and undertake a mission to rescue Gozumaru and Mezumaru from an enemy stronghold. In the Keikain Arc, he takes center stage in reclaiming the stolen sword Nenekirimaru from Oitekebori—an act that results in him reporting to his father and subsequently facing reprimand from Rikuo for his strict procedural compliance. For the Kyōto Arc, he initially remains in Tokyo to guard the Nura compound but later joins the battle in Kyōto against Hagoromo Gitsune’s forces. In the Hyaku Monogatari Arc, he is tasked with using his crow network to track disruptive yōkai throughout Tokyo. A glimpse into his family life occurs during the New Year's Arc, when he and his family visit their mother, Nuregarasu, on Mount Takao. The reunion is strained by her drunken frustration over their rare visits, culminating in a physical altercation between their parents that leaves the triplets in shock. His abilities are those of a Karasu Tengu: he commands the power of flight and demonstrates combat prowess by generating forceful whirlwinds, a technique he and his brothers once used to redirect an enemy’s fire attack. His most strategic skill lies in his command over crows, employing them for large-scale surveillance and intelligence gathering across entire cities, cementing his role as a vital asset to the clan’s information network.