Blood Reign: Curse of the Yoma

The first part begins after what appears to be a fierce battle, with several ninja from the Takeda clan retrieving weapons from their fallen comrades and enemies. Two other Takeda ninja, Hikage and Marou, are observing the process until Marou begins acting strangely. He momentarily tries to attack Hikage before returning to normal, seemingly shocked and frightened by what he has just done. The pair make their way back to the Takeda camp. That night, the clan leader, Shingen Takeda, is attacked and killed by a yōma. Shortly thereafter, Hikage learns from a Chuunin (a middle-ranking ninja) that Marou has deserted the Takeda and is at risk of exposing Shingen's death to other countries (i.e., other parts of Japan). He is ordered to track down Marou and eliminate him before word can spread, the Chuunin advising him to show no mercy, despite Hikage being his former best friend.

On his journey, Hikage is attacked by a pair of Iga ninja, whom he quickly dispatches. Later, while standing over a waterfall, Hikage reminisces about his childhood with Marou. He is brought out of his thoughts by an old man who claims he is "waiting to read Hikage's last rites." At the old shrine that the priest takes him to, he explains how people who have lost the will to live go to the waterfall to commit suicide by drowning themselves in the river below, and how he is there to comfort their souls. Knowing nothing of Marou's whereabouts, the priest advises that Hikage go to the village near the temple, as the sun will soon set. Hikage takes the advice and heads toward the village, encountering a young woman with a large scar on her left cheek along the way. The woman, named Aya, takes Hikage to the village and introduces him to several of the villagers, most prominently Taichi, a cheerful man who enjoys drinking and partying; and Ito, a woman with a suspicious air about her. During one of the villagers' parties, Hikage spots Marou for a brief instant, apparently entering a hut in the village, but is unable to find him in the following days, despite his intensive searching. One night, he meets with two of his fellow Takeda ninja to explain why he is staying in the village. After hearing he has seen Marou, and explaining to Hikage that this is where Marou's trail stops, they allow him to continue investigating the village, but remind him that he must show no mercy toward Marou.

The following night, Hikage sees Aya suffering from a nightmare. He holds her to try and comfort her, but immediately hears screaming coming from the forest. He rushes to the source of the screaming only to find Taichi and one of the Takeda ninja he spoke with earlier dead, along with another badly injured Takeda ninja. A spider yōma attacks, but Hikage uses shuriken to drive it off, seeing a brief, transparent vision of Marou in the yōma's wake. Before dying, the injured ninja reveals that Marou is a "child born of the ground" and that everyone in the Takeda village knew about it, but never discussed it. Left with this mystery, Hikage confronts Aya with Taichi's death, only for her to deny it. When Aya goes to her house to store some water, she hears Ito's voice asking her to do her a favor that night. Hikage goes down to the riverbank to find that the bodies of Taichi and the dead ninja, along with the bloodstains and weapons, have disappeared without explanation. Hikage hears Aya singing unusually late that night and goes to investigate. He finds Aya being held in a different spider yōma's mandibles and attacks it. It drops Aya, but soon runs away with Hikage in pursuit. He arrives at the temple and finds the priest from the waterfall standing before him on the path. He tells Hikage that he is erasing the villager's memories in order to ripen them for Kikuga no Miko's (the demon lord yōma of the land) revival after revealing the fact that he was the spider yoma from before. On the verge of death from a short battle, the priest/yōma warns Hikage about the suicide of the entire village should he die, which Hikage proceeds to kill him anyway. Aya wakes up and remembers how she got her scar, the priest's spell having worn off when he died. It was assumed that she drowned herself. Hikage finds a seemingly unconscious Ito and rushes to her aide. However, she wakes up and restrains Hikage but he was able to kill her also. Hikage enters the shrine and destroys the buddha statue to reveal an egg that he quickly cuts open. The egg opens to reveal Marou feasting on Taichi's severed head. A speechless Hikage approaches him, but Marou attacks him, causing the entire building to come crashing down. Outside, a fully dressed Marou walks away, giving the broken building a final glance before departing.

The next morning it is pouring rain. Reflecting on the night's events, Hikage suddenly remembers Aya and finds her body in the river only to find her dead. He returns to the village to find it wrecked and all of the inhabitants dead. An acquaintance of his, Kazami, arrives, telling Hikage that the Oda and Uesugi clans have found out about Shingen's death and that he does not need to pursue Marou anymore. Despite this, due to feeling guilt over not being able to save Aya and still seeking answers to why Marou betrayed their clan and became a yōma, Hikage leaves to continue his quest in search for his old friend.

Two years have passed since Hikage traveled to the west in pursuit of Marou, yet has not had any leads on his whereabouts. While on a beach, a kunoichi approaches him but Hikage quickly learns she is being chased by a group of ninja from the Kōga clan, led by Shiranui, who accused the kunoichi for killing their leader. She denies having anything to do with it, and soon Hikage ends up fighting them as well. Shiranui stumbles into the ocean from the defeat and is trampled to death by Majumi no Miko, the demon lord of the sea. Hikage asks for Marou's whereabouts, only for Majumi to mock their friendship. Angered, Hikage attacks Majumi and barely manages to escape. Meanwhile, Marou converses with Shiratsuyu, a snake yōma, on what to do about the war between the Oda and Takeda clans. Marou orders Shiratsuyu to kill Hikage while he turns Mikawa into a "living hell".

The kunoichi, later revealing her name to be Aya, travels with Hikage to a nearby village that has seemingly been untouched by the war. Aya goes to one of the villager's huts to stay for the night but soon comes upon a headless baby and the two learn that the entire village is dead, yet still walking. The village is shown to be in ruins and the two spend the night in a wrecked hut. The next day, Hikage leaves Aya behind and continues his search. He runs into and battles Shiratsuyu, along with Mai, a female butterfly yōma, and a tree yōma, Yoki. Meanwhile, Aya, upset that Hikage left her behind, encounters Kotone, a spirit of a woman. They talk briefly before Yoki captures them to gain an advantage over Hikage. With some difficulty, Hikage slays Mai and Yoki. Shiratsuyu, on the other hand, is possessed by Kotone and vanishes.

After traveling for a while with no recent yoma attacks, Kazami appears before Hikage and attacks him. He claims to have been ordered by Katsuyori Takeda, the Takeda clan's new head, to kill him in order for Kikuga to be willing to lend them the power of the yoma. After a hesitation, Kazami is mortally wounded by Hikage as a result. He expresses no true desire to kill Hikage and does not wish for the power of the yoma. As it turns out, Marou only told the Takeda that he would help them in order to create more hatred and grudges during the final battle at Mount Nagashino. During which, the entire Takeda clan was decimated by the Oda, leaving Hikage no home to return to.

Hikage gathers his supplies and plans to head to Mount Nagashino. Aya begs him to abandon his desire to hunt Marou and for him to stay with her, but he does not listen, leaving a sobbing Aya behind. Upon his arrival at the battlefield, Hikage fights off rock formation of hands before meeting face-to-face with Marou, the former asking why he has become Kikuga. He mocks his former friend and explained that he grew tired of living as a ninja and rationalizes his change into Kikuga. He justifies sparing Hikage's life so that he would eventually join him as a yōma, thereby transcending humanity. Maru puts Hikage in a trance and proceeds with Hikage's yoma transformation but he awakes when Aya calls out to him despite being trapped by rock hand formations. Marou, upon seeing his friend's refusal, transforms into a red-eyed wolf-faced yōma. He is joined by Majumi and proposes the two be joined together. Aya wraps her wires around Majumi attempting to stop it, but it dragged her along the ground and stomped on her face, knocking her out. The two demon lords then dissolve and merge into a creature resembling a wolf and a centaur. It is shown to have control over land and can use telekinesis to break objects and hold Hikage in place. Knocking Hikage from a cliff, Marou again proposes that Hikage joins them as a yoma. But when he again refused, a frustrated Marou attacks and blinds him. Hikage manages to cut Maru from Majumi, reverting Maru back to his original yoma. Moaning in pain, Marou reminisces the two of them as kids running through the fields. He remains distracted long enough for Hikage to slice his throat, ending the threat of Kikuga and the yōma. Marou, back in his human form, turns to face Hikage, who warmly smiles and offers his hand. Before Marou can grasp it, he falls over dead, and within moments Hikage collapses as well. The ground beneath the former demon king crumbles and he falls into the darkness, leaving his childhood friend alone and unconscious.

Later, Hikage awakens in a hut with a fire burning. He sees Aya just returning with water and speculates that she was the one who carried him back. She is now sporting a large scar on her left cheek similar to that of the original Aya, which was caused by Majumi. She becomes ashamed but is comforted by Hikage who accepts her for who is. In the netherworld, Marou's corpse lays still as Kotone, still possessing Shiratsuyu, comes towards him. A flashback reveals that Marou was her lover. Kotone decides to give Marou her life-force so that he can be reborn and then disappears.

Some time later, Hikage and Aya have resumed their travels. They stumble upon a dead woman and her newborn son, who is crying hysterically. Aya picks up the infant and calms him; Hikage stares at the baby boy for an inordinate amount of time. Marou's voice is heard, telling Hikage that being a human is "so boring".