Menomaru is the main antagonist of the first Inuyasha movie, Inuyasha: Affections Touching Across Time. He is the son of an extremely powerful moth daiyokai named Lord Hyoga who was defeated by Inuyasha's father 200 years before the main storyline. Menōmaru and Hyoga's power were both sealed to the ancient Tree of Ages. When the Shikon no Tamawas shattered, one of the shards revived Menōmaru and he embarked on a quest to obtain his father's power. After discovering that one of the Great Dog Demon's swords, theTenseiga, did not possess the destructive aura required to remove the seal on Hyōga, Menōmaru and his servants planned to steal the other sword, the Tessaiga, which did have the power.
Upon discovering that the fang had a barrier which prevented demons from using it, Menōmaru lured Tessaiga's owner, thehalf-demon Inuyasha, to his hide out under the Tree of Ages. In an effort to save Kagome Higurashi, Inuyasha was tricked into destroying his father's fang, breaking the seal on Hyōga's power. Thus, Menōmaru was able to absorb his father's power to become the new Lord Hyōga. Menōmaru then began absorbing souls to complete his transformation. Despite his success, Menōmaru was unable to destroy Inuyasha and themiko Kagome before he emerged from his chrysalis, and squared off against them for a final confrontation.