The third InuYasha film, InuYasha the Movie: Swords of an Honorable Ruler, which is not directly based on the manga, gives Inuyasha's mother the name Izayoi (十六夜?). The film shows her on the night of Inuyasha's birth as a captive of Setsuna no Takemaru and his samurai, who plan to lure the Great Dog Demon into coming to rescue her so they can kill him. Izayoi pleads with Takemaru to leave and save his own life, but Takemaru claims he loves her and stabs her through the chest with a spear. Before she dies, she is able to give birth to Inuyasha. The Great Dog Demon, already injured by his battle with Ryūkotsusei, fights his way through Takemaru's men and the burning building to reach his dead lover and his newborn child. He uses the Tenseiga to restore her to life, then covers her with the Robe of the Fire Rat and orders her to flee. Before she leaves, he names his son Inuyasha. The Great Dog Demon remains behind to fight Takemaru to the death as Izayoi flees with their child.
In the anime adaptation, she is voiced by Kikuko Inoue. In the English dub, she is voiced by Alaina Burnett.