Season 1 - Episode Guide

A deadly virus sweeps the earth, leaving behind only children and vampires. Yuuichi Nakamura and the other orphans are captured by these vampires and are forced to provide them blood in order to survive. Fed up, they plan on an escape...

Four years later, Yuichiro Hyakuya is a soldier in the Japanese Imperial Demon Army, but he gets suspended for insubordination. As punishment, he attends a school with the order to "make friends.

Yu, Yoichi, and Shinoa go to a restricted area to save someone who was possessed by a demon there.

Mikaela, who was thought to be dead, was actually turned into a vampire by Krul and is working with them. Meanwhile, Yuichiro starts his first day at the Extermination Unit's training school, and already he gets into a fight with one of his classmates...

Eager to obtain the Cursed Gear, Yuichiro tracks down Guren and persuades him to provide him a chance at the Contract Ceremony. Passing Guren's test, Yuichiro, Kimizuki, and Yoichi puts their lives on the line to make a contract with the demon kings.

Kimizuki, Yuichiro, and Yoichi fight against the hallucinations caused by the Black Demons they chose in order to attain their power. They face their tragic memories and fight for control.

Yuichiro, Shinoa, Kimizuki, and Yoichi meet Mitsuba Sangu and form a squad lead by Shinoa. They leave the walls of the Japanese Imperial Demon Army to exterminate vampires. In the meantime, Guren takes a separate route.

With the information obtained from the little girl they saved, Yuichiro and his squad goes to the subway station where the vampires are in order to free the people. However, they quickly learn that everything was a trap from the start...

After saving the captured people from vampires, Yu and his unit reach Shinjuku. However, by the time they reach there, the war had already begun and some vampires had gotten through. To prevent Shijuku from falling, they must fight off the vampires.

Learning that Mitsuba, Kimizuki, and Yoichi are in a pinch, Yu and Shinoa rushes to their rescue. Meanwhile, Guren and his troops fight off the vampire's main forces, but Ferid's strength seems to be out of their league, cornering Guren in a tough spot.

Finally, Mika and Yu reunite, but their circumstances does not allow for much time. Mika tries to "save" Yu from the humans, who have been experimenting on him, but Yu wants to save his squad. Torn between Mika and his squad, something in Yu is awaken...

Trying to figure out what happened to Yu, Shinoa tracks down Guren and asks what he's conspiring to do. However, Guren doesn't answer and keeps it a mystery. When Yu finally wakes up from a seven-day-coma, he explains he doesn't remember what happened.

Shinoa instructs Yu to follow instructions written on notes, a balloon and the teacher's back in a prank.

During the training sequence, Shinoa gives Yu his hearts desire, ranging from silver and golden axes, to Shinoa merchandise.

In Sanguinem, a young Yu asks a young Mika what's on his mind. After some hesitation and being told to let it out, Mika declares that he's got more charm as a main character. Shinoa appears and agrees, but more so if she were a magical girl main character. Guren states who needs main characters when you have him.

In the campus room where Yu was recovering, Shinoa, Yoichi and Yu play a hand slap game to which Yu loses each round. Shinoa and Yoichi are pleased with their winning prize of Yu's drinks.

Yoichi tries to calm an arguing Kimizuki and Yu, Shinoa knows of a way they can get along. In a library (brief scenes of which are shown only here) they find a book of secrets, drinking a bitter tasting truth serum, Yoichi's dreams come true. Kimizuki and Yu get along by behaving likes dogs as a side effect and they chase Yoichi around before fighting again. They drink the antidote which results in Yu noticing something he didn't notice before in Yoichi who runs, Kimizuki is also affected by the love potion, before noticing Yu's 'kind of nice' hair. Yoichi's wish came true; to which Shinoa has baseball bats as the remedy to get them back to themselves.

Combat ready for Shinjuku, Kimizuki makes a wrong turn and drives the squad to Ueno, at the Saigo Takamori Statue. Kimizuki makes another turn but ends up at the statue of Hachiko in Shibuya. He makes another turn where he ends up at the Statue of Liberty replica in Odaiba. Kimizuki admits that he's lost.

After a briefing from Guren, and before setting out on their first mission, Yu fails to parry Mitsuba's kicks and surprise moves, including a tickle attack.

Guren leaves the meeting with Tenri Hīragi, only to return to the same room each time, much to the delight of Shinya.

After getting demon weapons before heading to Shinjuku, Shinya appears out of nowhere to share various memories of Guren. They include a picture of him smiling with Yu, drinking a papaya flavored drink and then spitting it out. Some others that are some include Guren with a kitten, stubbing his toes and spilling milk in the process, then crying in agony. Shinya declares he will cherish the collection but a fiery livid Guren draws his sword and attacks.