Haunted by the untimely deaths of his mother, little sister, and a childhood friend, listless high schooler Haruomi Io has trouble engaging with anything or anyone. Of course, that doesn't mean others have trouble engaging with him-a fact he discovers to his dismay when he finds himself the target of a trigger-happy group calling themselves the "Seventh Gospel Organization." Having newfound enemies may be rough, but Haruomi's unexpected ally in the form of a demoness calling herself Zilch may turn out to be even more of a handful...Still, there's something to be said for a dose of the supernatural (and more than a few buxom girls) when it comes to casting off the doldrums!

Haruomi and the Seventh Gospel Organization have arrived to rescue Murohime, but Hellentza has designs on the buxom agent as well. What's more, Zilch's bizarre behavior only adds to the chaos-will the true identity of her second personality finally come to light?! Discover the fate that awaits the heroines in the climactic conclusion to Demonizer Zilch!

Haruomi awakens to the power of the Ring of Solomon and decides to take up the role of Annihilator in the Seventh Gospel Organization, a society of demon hunters, in order to grant Zilch her wish. Under orders from the organization, Haruomi and Zilch begin a covert investigation to find a new "branch" at Kanmeikan High School, where they're joined by none other than Murohime. What adventures await them there...?!

Ever since his sister disappeared ten years ago, Haruomi's held a grudge against the mysterious organization Goetia. But when the demonic "Branches" Leraje and Berith go after both Haruomi's dad and Zilch, things get even more personal! Will Haruomi and Zilch be able to fend off the encroaching devils...and get into some sinful situations while they're at it?

While Yuuto's away, the Nine-Tails comes to play! Himari and Shizuku are home alone when their foxy enemy drops by out of the blue to hit the pair with a vicious assault that forces them to flee. Meanwhile, Kuesu, having rushed after Yuuto and company, looks to launch the decisive battle with Shuten-Douji all on her own?! All involved will be reeling with passion and loss before this battle ends...

(Volume 3) Having safely completed their infiltration mission, Haruomi and the gang add Hato Mitsukuri to their team, but then "Goetia," who has targeted Zilch, sends out the assassin "The Blue Arrow Marquis" Leraje to attack her!! Zilch is in a hard fight against this "Branch," who uses magic arrows, but meanwhile the demon "Duke" Berith starts closing in on the Seventh Gospel Organization where Haruomi's father is...!? In this slightly lewd and sinful fantasy, the curtain rises on the astonishing "Goetia" arc!!

Sylvia, the fourth princess of Lautreamont, has grown up feeling overshadowed by her eldest sister's accomplishments, while Veronica, a battle-hardened war hero, is ruthless in demanding that her younger sister live up to her expectations. When the infamous terrorist known as Avdocha comes to Lautreamont, wanting nothing less than to take Veronica's head, the younger Sylvia becomes her bait that will lure Veronica into a trap. Ash Blake must use his ability to command any dragon at will in order to rescue Sylvia. But can his heroics help Sylvia hold her head high and fight back as a proud princess of Lautreamont?