Onmyou Taisenki

Riku feels that there is no use in fighting Mikazuchi right now, so he and Souma head back to Tenjinchou on a bus. The ride home gets disrupted by a giant spider Youkai known as Tsuchigumo. Riku, Souma, and their Shikigami manage to destroy the Tsuchigumo and continue their ride home. But the ride gets disrupted again by a large Youkai. This time, however, Momo and Rina join the fight and summon their Shikigami, Houjou no Nene and Iyashibi no Hiyoshino. Huh?!

It's summer, but it's snowing! The strange weather is due to the Daikimon that the Chi-ryuu opened. Speaking of the Chi-ryuu, they have initiated more of their plans by opening the 4 Kimon. Mikazuchi takes advantage of the abnormal weather change by announcing that he and the Mikazuchi group will care for the public by lowering the prices for vegetables, despite the cold weather. The Mikazuchi Group's stocks go up. By controlling the food, they will control the country's government. Also, since resources are scarce because of the cold climate, Mikazuchi's oil reserves will give the Mikazuchi Group control over energy maintenance and casting board. Teru comes back and reports that there are Youkai terrorizing people. As Head of the Ten-ryuu, Riku leads a Youkai extermination.

Yakumo is attacked by Shoukaku, a Toujinshi of the Jin-ryuu, and his Shikigami, Oobi no Yatarou. Yakumo fends off the attackers and discovers what the Jin-ryuu are planning. Masaomi gives Riku information about the Chi-ryuu's 4 Kimon. While on their way to one of those 4 Kimon, Riku, Souma, and Nazuna meet an kind-hearted, inexperienced Chi-ryuu Toujinshi named Subaru and his Shikigami, Tsubaki no Houshun. When Riku and the gang befriend Subaru, Houshun is destroyed by the Ten-ryuu Suppression Department Chief of the Chi-ryuu, Taizan, and his Shikigami, Souka no Onishiba.

Following Taizan and Onishiba into a Kimon portal, Riku and Kogenta end up in Tousa of Shikoku, where a local village's crops have been growing immensely. But the only crops worth of value are the mandarin oranges, which are owned by the Mikazuchi Group. Riku and Kogenta then fight the Chi-ryuu Daikimon Construction Head, the elderly Nankai, and his Shikigami, Shuusui no Namazubou. Will Riku and Kogenta be able to defeat Nankai's 30-year bond with Namazubou?

Yuuma must protect Mizuki while fending off two Toujinshi of the Jin-ryuu, Shoukaku (Shikigami - Oobi no Yatarou) and Zenjou (Shikigami - Tsubaki no Kantarou). Also, Souma reveals the tragedy of the Asuka family.

Teru needs help from Riku and the gang at the beach. There is a dangerous Youkai that eats humans, two of which are a baby's mom and dad. Since Teru is close to the parents, he grows angry. His madness is even scarier than the Youkai!

Taizan has one of his subordinates, Murasame (Shikigami - Shirogane no Chiyorozu), set a trap for Riku, saying that his parents have been found in the Fukumaden. The trap was meant to make Riku lose his fighting spirit, but it actually made Riku so angry that he uses the Daikoujin and has Kogenta destroy everything in the Fukumaden.

Yuuma and Mizuki reach an exit from the Fukumaden, but then Masaomi appears and blocks their escape. So, Yuuma and Rangetsu will have to fight Masaomi and Kibachiyo once more.

Yuuma returns from the Fukumaden. He is offered to become in charge of the Daikimon, but he declines. Now, Yuuma and Rangetsu will have to deal with Mikazuchi and his Shikigami, Akagane no Itsumu. Elsewhere, Riku's boat tournament takes place. However, the Chi-ryuu's Mutsuki returns and attacks Riku. Mutsuki also has a new partner, Madoka (Shikigami - Uzubimi no Koufuku).

Riku and Kogenta meet a Shikigami named Genbu no Koroku, who knows of a way to repair the Kotetsu sword. Riku and Kogenta also find one of the Chi-ryuu's Shikimon. While Riku's friends work with Koroku repairing the sword, Riku and Kogenta fight the Chi-ryuu's Oosumi and her Shikigami, Kanro no Miyuki.

Relationships are put to the test as Mikazuchi tells Yuuma to confront Taizan and as Riku and Kogenta face the Chi-ryuu's Kureyama and his Shikigami, Enoki no Kongou.

Riku and Kogenta discover the truth about Masaomi and Kibachiyo and hear what Masaomi says about Kogenta. Yuuma and Rangetsu take on Taizan and Onishiba. Yakumo and his 5 Shikigami battle Shukaku and Yatarou once more.

The Heads of the Ten-ryuu and Chi-ryuu, Riku and Yuuma, fight Mikazuchi in one gigantic battle.

Riku and Yuuma use their new Master Drives to fight the Itsumu-possessed Mikazuchi.

Things have quieted down until Yuuma and Rangetsu challenge Riku and Kogenta again. But they will soon learn that a greater evil is upon them.

Youkai flood the city, people turn into stone, and Masaomi/Gasshin reappears in front of Riku.

After fighting Masaomi/Gasshin and Kibachiyo, Riku and Yuuma have to work together as they try to find and confront Utsuho.

Riku and Yuuma face one Jin-ryuu trap after another. Divine punishment from 1000 years occur. Masaomi/Gasshin's sister Usubeni is revived.

Souma goes off on his own to rescue the kidnapped Nazuna.

Yakumo and Masaomi/Gasshin fight once again. For Yakumo and his five Shikigami, it will be their last battle.

Masaomi/Gasshin meets with Riku and reveals everything that has happened in the past.

While Riku meets the resurrected Raihou and talk about what it means to be a head, Yuuma fights alongside Souma and the others against Shoukaku and his Yondaiten-empowered Shikigami.

While Masaomi/Gasshin and Kibachiyo fight Taizan and Onishiba, Riku is stuck in the illusion, created by Utsuho, that he is with his parents.

Riku and Yuuma along with their friends finally confront Utsuho, who reveals to be able to manipulate the bonds between Toujinshi and their Shikigami.

The 3 Masters, Riku, Yuuma, and Masaomi/Gasshin, all fight Utsuho in one final battle.

The Shikigami return, despite Utsuho killing all of them. Utsuho also discovers why all the Shikigami came to him 1200 years ago. Afterwards, everybody has a happy ending, and a certain someone returns to Riku.