Season 1

While cleaning out some books from the store room, Ushio stumbles upon a door. Upon opening it, he finds a beast inside, which is stuck because of a spear holding it in place. The beast asks him to remove the spear, since only a human can do it. But since he says that he'll eat Ushio and wreck havoc among humans, Ushio doesn't help him. The beast's aura leaks, attracting many other yokais and Ushio is forced to free him to exterminate all the other yokais.

While cleaning in the school, Asako and some other girls get trapped by a Stone Eater yokai.

A girl named Reiko is carrying a death wish, since her father, who has turned into an oni is haunting her and hurting anyone who gets close to her.

The Gamin (a family of 5 demon heads) are released and they go eating any girl around the city who bears a resemblance to Mikado Hizaki, who had sealed them a long time ago. Mayuko Inoue bears an uncanny resemblance to her and is out alone, shopping.

An exorcist named Hyou is searching for the yokai, who killed his wife and 5 year old kid and took out his right eye and left three long scars on his face, to exact revenge. He thinks Tora might be the yokai and arrives to Japan.

While at the beach, Tora is requested by Umizatou to get rid of a yokai whom he is unable to subdue. The yokai is made of souls of those who died at sea and it is eating both humans and yokai. Tora gets caught when the yokai tried to eat him. Asoko and a little kid get trapped too. Its up to Ushio to save them.

Ushio demands his mother's whereabouts from his father, who promptly escapes. After Shigure reports about Ushio, the Beast Spear and Tora to higher ups, he is asked to monitor both Ushio and Tora to see their worth. When they are attacked, Shigure deems Ushio and Tora to be worthy and gives money to Ushio to go meet his uncle, and learn more about his mother from the journey.

While traveling to Hokkaido by air, Ushio and Tora meet the demon Fusuma who tries to crash the plane to savor all its occupants.

Ushio is requested by the Kamaitachi siblings to kill their third sibling as he is causing trouble to humans, after they are forced to move out of their home in the mountains.

Ushio sees a girl at an onsen. Later he saves her from an accident. She is Saya Takatori, the white haired girl, who is guarding the Zahiki Warashi of the Takatori house, Omamori, from leaving so that the house remains prosperous.

Ushio is staying at the Kamaitachis' house when he sees Asako calling out Mayuko with a face full of fright. After asking a mirror elder, he comes to know that a mirror demon has kidnapped Mayuko inside the mirror.

After parting with the Kamaitachi siblings, Tora and Ushio head to their next destination Touno. On the way however they are attacked and separated by youkai who wish to kill Ushio. A conversation with a friendly kappa youkai reveals that the true reason is his mother and tells a story of Hakumen no Mono, a ruthless human and demon-killing youkai from China that retreated from a war with both factions long ago. Before he can finish with the truth about his mother, Ushio must flee from the attacking youkai once more. Elsewhere, Tora struggles to understand why he's changed so much when challenged by a fellow youkai past, Hitotsuki, one who is part of the group hunting Ushio.

After escaping the attacking youkai and saving an old man, Ushio recovers his strength and rests at a bakery in a small town. Ushio relates to them his struggles and how many people have been endangered since he pulled the spear. Ushio is reunited with the Kamaitachi siblings and the team tries to resist the youkai forces. They are saved by Tora and escape. However, a mist warps Ushio to a humble mansion of the leader of the mountain youkai. The leader relates the remainder of the tale of why the youkai seek vengeance against Ushio. His mother is part of a line of women tasked with upholding a barrier keeping Hakumen no Mono dormant yet preventing the other youkai from exacting their revenge on the monster. After Tora battles Hitotsuki, all the youkai cede and allow Ushio to continue his journey.

Hakumen no Mono, sensing the coming of the Beast Spear sends out its familiars or hiyou to destroy the spear and it's wielder. Ushio ends up encountering one of the successors trained by the Kouhamei sect to wield the Beast Spear, Seikimori Hinowa. She demands the spear, stating that Ushio's lack of training has been the paramount factor in why so many people have been put in danger. Ushio ends up giving up the spear but when Hinowa encounters a more powerful hiyou, she finds that it will not lend her it's power. Ushio and Tora return to save her and she acknowledges Ushio's worth for a time. Later, as the duo try to head to their next destination, Tora is sidetracked by a duel with another one of the successors, Akiba Nagare. Tora defeats him and relates that the reason he continues to follow Ushio is that he's never bored when he's with him.

As the Hiyō possess a bus in which Ushio is traveling to kill him, along with the rest of the passengers, Ushio must rely on the help of Akiba Nagare and Tora to stop them.

Another of the successors, Satoru Moritsuna, attacks Ushio, even as he is accompanied by Jun Moritsuna, Akiba Nagare and others. After determining that Satoru Moritsuna's head is possessed by the Hiyō, Ushio has to decide whether to enter Moritsuna's body to defeat the Hiyō, and risk himself turning into a monster, or not.

As Ushio turns into a monster, all the people he has met and saved gather to save him. Jie Mei gathers the five girls Ushio has strong bonds with - Asako, Mayuko, Reiko, Saya and Yū to save Ushio. They are to comb Ushio's hair using the comb that his mother gave him, to return Ushio back to his human self.

After the girls finally manage to save him, Ushio enters the cave where Hakumen no Mono resides along with Tora.

Once inside the cave, Ushio and Tora are carried over to the past by a time manipulating yōkai. There, they bear witness to how Hakumen no Mono first attacked the king and people of China, destroying the city and killing the parents of Jie Mei and Giryō.

Ushio is further witness to the creation of the Beast Spear. As Jie Mei and the time manipulating yōkai bring them back Ushio and Tora to the present, Jie Mei also tells Ushio the reason why the barrier was created around Hakumen no Mono and also about his mother.

Kirio pays a visit to Ushio to take the scythe from him. But they are interrupted when Kuragi, an insect like yōkai, who is avatar of Hakumen no Mono attacks the Kōhamei Sect headquarters, unstoppable by any. Ushio and Kirio are taken there by Shigure where Ushio meets Mikado Hizaki. Later, as Ushio falls after failing to defeat Kuragi, Mikado Hizaki freezes the monster and Kirio finishes it off. Mikado Hizaki dies after exhausting her powers. Afterwards, we see Kirio telling his mother how he finished the monster himself, and that no one believes him when he says that they don't need the Beast Spear to defeat Hakumen no Mono. She gives him the Beast Spear's red cloth and tells him that if no one believes, it is ok to break the spear to show them so.

As Ushio becomes depressed due to his inability to save Mikado Hizaki, Tora tried to fire him up by verbally insulting and fighting him, but leaves once it is proved useless. Kirio comes to steal the Beast Spear from Ushio along with a few supporters and snatches it from Ushio using the red cloth. When Nagare arrives to warn Ushio, he is joined by Tora in the search of Kirio. Hinowa joins Ushio in the search of the Spear. The group arrive at a facility and find the diary of Kyōra, the creator of the Elzaar Scythe. They come to know of a woman named Towako (who is the one who took the red cloth and acts as Kirio's mother) who helped him greatly in achieving success in his researches in creating the Elzaar Scythe, Kuin and even Kirio.

The truth about Kirio and the Elzaar Scythe is revealed, and Ushio and Tora settle things with Kirio and Towako once and for all.

Mayuko is invited to a strange dinner party and Tora eats crab gyoza burgers.

Another morning fighting with Tora followed by going to school with Asako. However, an organization named HAMMR breaks the usual cycle. The three mad scientists of HAMMR kidnap Ushio and Asako and Tora go after them in an attempt to save him.

Hakumen's impending arrival causes a monster disaster, and also adversely affects the people involved.

Ushio, anxious over the approaching decisive battle with Hakumen, runs into Asako on the way home from school and ends up arguing with her as usual.

Upon getting a premonition that the Beast Spear would break, the yokai chiefs from all over make a collective decision.

Mayuko, Kirio, and Kuin are all doing what they can to stop Hakumen no Mono. Meanwhile, Ushio runs into the exorcist, Hyou, again. Because of his magical eye, Hyou did not forget about Ushio's existence. Hyou comes to visit Ushio at his home, and they encounter azafuses as well as Guren, and learn what Tora might actually be.

A mysterious ghost appears in front of Atsuzawa and calls herself Jie Mei. She says she has a favor to ask him in regards to Hakumen no Mono... Meanwhile, Ushio and Tora are asked to come meet some people who want to see them. While they are on the way to meet these people, they run into Nagare, and Ushio can't hide his surprise. The happy reunion is cut short by some shocking news...

After being tricked by Hakumen no Mono, the JASDF prepare to send subs to destroy the stone pillar where Ushio's mother is, as she keeps Hakumen sealed. Ushio heads to Okinawa to stop them, but runs into Nagare, who seems to have switched sides. Ushio leaves Nagare to Tora, and hurries to stop the subs. Nagare and Tora go all out in battle, and Asako finds out a secret about Ushio...

Ushio heads to the stone pillar in order to save his mother from Hakumen no Mono. He approaches her quietly in the cave and she softly calls his name. They get to share a heartwarming moment together, but then a terrible sound interrupts their reunion. Torpedoes break through the barrier, and then...

Earthquakes occur all over Japan. People are filled with great fear that give Hakumen more power. Ushio confronts Hakumen with a strong hatred, although Sumako has stopped him.

The prophecy comes true, the Beast Spear breaks into pieces during the fierce battle. Ushio sees someone's past in ancient times as a dream while he is sinking in the ocean.

Kirio tells Sumako and Mayuko that he found out something about the past of Tora and other Azafuses. Meanwhile, small pieces of the Beast Spear save Ushio from the bottom of ocean, and then, they kill Hiyou which has possessed billions of minds.

Ushio and Tora confront Hakumen again. Hyou makes a duel with Guren to revenge his wife and daughter.

Mayuko pulls her soul out of her body to support Tora. The allied forces of human and yôkai restore the bonds among themselves to beat Hakumen.

There are three survivors in mystical barrier, because Hakumen strikes back with poison. The last battle of Ushio and Tora versus Hakumen enters in the final phase.

Hakumen crushes its eyes itself to overcome the fear of the Beast Spear. Tora wants to save all the people even if it has to sacrifice itself, and tells the strategy to Ushio.