"Anal Backer" is a manga series that blends elements of action, comedy, and fantasy. The story centers on Kakeru Shiki, a high school student who becomes entangled in a supernatural conflict after encountering a mysterious girl named Miu Fujisaki. Miu is revealed to be a "Backer," a being with the ability to summon powerful creatures known as "Anchors" to fight on her behalf. These Anchors are summoned through a unique and unconventional method involving anal stimulation, which serves as the series' central comedic and thematic hook.

Kakeru is unexpectedly chosen as Miu's Anchor, granting him immense physical strength and combat abilities when summoned. However, his role as an Anchor comes with significant challenges, as he must protect Miu from other Backers and Anchors who seek to eliminate her. The world of Backers is governed by a ruthless hierarchy, with battles often determining the survival and dominance of individuals within this hidden society.

As the narrative progresses, Kakeru and Miu form a reluctant partnership, navigating a series of intense battles and uncovering the deeper mysteries surrounding the Backer system. The story explores themes of trust, loyalty, and the consequences of power, as Kakeru grapples with his newfound abilities and the moral dilemmas of his role. Supporting characters, including rival Backers and Anchors, add complexity to the plot, each with their own motivations and backstories.

The series balances its action-packed sequences with humor, often derived from the absurdity of the summoning mechanics and the dynamic between Kakeru and Miu. The interplay between the fantastical elements and the grounded, everyday struggles of its characters creates a unique narrative tone. "Anal Backer" maintains a steady pace, blending episodic battles with overarching plot developments, ensuring a mix of immediate excitement and long-term intrigue.