THE REVIVAL OF THE TRUE FOURTH PRIMOGENITOR IS NIGH! When Kojou Akatsuki was a junior high school student, he met a vampire named Avrora...and then he saw her again when travelling to the hospital to visit his sister. When Kojou learns this mysterious, quiet girl could be the key to saving Nagisa's life, he helps her escape the Magna Atraxia Research lab. With the arms dealer Zaharias planning to use Avrora in his Blazing Banquet, can Kojou stop the revival of the true Fourth Primogenitor and save Itogami Island?

Time is running out for Kanon Kanase. If they can't stop the faux-angel ritual in time, she'll ascend from realm of mankind and become something truly inhuman. Will the Fourth Primogenitor be strong enough to stop this madness before it's too late? The Amphisbaena arc reaches its heart-pounding conclusion!

NO REST FOR A PRIMOGENITOR… It’s a new term at Saikai Academy, and fortunately for Kojou, hehasn’t been held back a year! Freed from his constant work defending Itogami Island, he is ready for some peace. However, an entirelynew demon beast appears, and when Rui and Yuno are dispatched to deal with it, they are gravely wounded. Kiriha forms an unlikelyalliance with Shizuri, who is dead set on avenging her friends. Meanwhile, the Japanese government has concerns about Yukina’s ability to continue observing the Fourth Primogenitor, so the Lion King Agency readies a replacement. As Yukina frets over this threat to her position, her stress only grows with the arrival of a mysterious girl who looks exactly like her!

Kojou Akatsuki lives on the artificial island of Itogami, and he has a secret: He's the "Fourth Primogenitor," the most powerful vampire in the world. He's carefully kept this dark knowledge from his family and friends, but one day, a beautiful girl named Yukina Himeragi appears before him and tells him that she knows who he really is--and that she's been sent to...kill him?!

When all the students depart for a school field trip to the mainland, Kojou is delighted to hear that he'll finally get a chance to be free of observation for at least a little while, whereas Yukina has mixed feelings about the whole situation. But events move quickly when an alchemist by the name of Kou Amatsuka appears, with the goal of reviving the holy grail of alchemy--a liquid-metal life-form known as "Wiseman's Blood." As the crisis deepens, even Asagi becomes involved when this alchemist's relic grows more and more uncontrollable. What can the world's strongest vampire do?!

After partnering with Natsuki Minamiya to capture the Masked and end the destruction in the sky, Kojou and Yukina are shocked to discover one of the winged girls is none other than Yukina's classmate Kanon Kanase! When Kanon disappears, Kojou and Yukina seek out her adoptive father, a researcher at megacorp Magus Craft, Inc. Far from the professional meeting they expected, the two find themselves abandoned on a deserted island! It is deserted...isn't it?!

Yukina is trapped in a pitched battle against Astarte the homunculus, and she's losing--when who should come to her rescue but the very boy she's been assigned to observe, Kojo Akatsuki! Akatsuki tries to end the clash, but Astarte's familiar, the fearsome Rhododactylos, isn't going to let that happen. Is this a fight that only an awakened Fourth Primogenitor can finish?

Kojou and Yukina join forces with Natsuki Minamiya to protect Itogami City from a new threat from the skies--but even Kojou's Beast Vassal can't take this new foe on, and who should rescue them from their predicament but Kojou's sister's friend, a silver-haired girl named Kanon Kanase! But when Kanon disappears, Kojou and Yukina may find that there are some problems not even the world's mightiest vampire can solve!

Nagisa has collapsed! Kojou rushes to the hospital, but suddenly a mysterious girl appears, and she looks just like Avrora, the former Fourth Primogenitor. She backs Kojou into a corner--but is she the real Avrora? Through this encounter, Kojou regains his lost memories, what will he remember? Finally, Kojou's past and the secrets of the Fourth Primogenitor are revealed!

WHEN ALLIES BECOME ENEMIES, WHO CAN YOU TRUST? New Year's Day is right around the corner on Itogami Island, and everyone is getting ready to celebrate! ...Well, almost everyone. Nagisa, off on a trip to the mainland to visit her grandmother, hasn't been returning any calls or texts. Equally troubling is Yukina's sudden and complete loss of contact with the Lion King Agency. When Kojou and Yukina's frantic attempts to find answers reveal evidence of a magical incident, Kojou decides to risk everything and travel to the mainland to find Nagisa himself. But in hismost desperate hour, an unexpected adversary stands in his way...