Linebarrels of Iron (鉄のラインバレル, Kurogane no Rainbareru) is a Japanese manga series created by Eiichi Shimizu and Tomohiro Shimoguchi.

[6] The story centers on Kouichi Hayase, a fourteen-year-old boy living a mediocre life, until an accident turns him into the pilot of a gigantic robot called "Linebarrel" and leads him to encounter a mysterious girl.

[5] The Linebarrels of Iron story takes place in an alternate universe in the year 2019, centering on a junior-high school student named Kouichi Hayase, who escaped his daily life of being ridiculed as a child by daydreaming about being a hero.

Due to this "accident", Kouichi is left in a coma for half a year, and upon awakening, found himself with strange powers, including superhuman strength.

This leads him to encounter Emi Kizaki, a mysterious amnesiac girl whose unknown past seems to be related to Linebarrel.

The series primarily focuses on Machinas, robots which are not manufactured by humans and are powered by nanobots called D-S.O.I.L., also known as Drexler S.O.I.L., which also enable them to regenerate after being damaged.

It is revealed mid-way through the manga that a majority of humanity was wiped out after the development of Nanomachines and the Machina due to a kill-switch built into their DNA.

Similar to a hive mind, this virtual collective unity threw away individuality and any sort of vestige of human feelings for the sake of power, becoming one cold, ruthless mechanical being bent on a continuous, endless expansion of itself.

Referred to as "Central", this hive mind acts in a way reminiscent of the machines from the Matrix trilogy, even having its own enforcers to hunt down and destroy whoever is perceived as a hindrance.

Akita Shoten also published a book containing details about the anime adaptation, simultaneously releasing it on the same day as the tenth volume.

[7] An official English language Linebarrels of Iron website was put up just before the Anime Expo in order to promote the American premiere of the series.

Other special screenings for the first episode also took place in France's Japan Expo in July and Germany's Animagic 2008 in August.

The opening theme is "Kitei no Tsurugi" (鬼帝の剣, Sword of the Demon King) by the Japanese band Ali Project, the ending themes are "Ame ga Furu" (雨が降る, Falling Rain) and "Remedy" by Maaya Sakamoto, and the insert songs are "Kokoro no Mama ni" (心のままに, State of My Heart) and "PROUD" by Lisa Komine.

"[22] Dani Moure of Mania, an entertainment website, believes that the first episode "does a good job of introducing the premise of the show," but finds it "predictable and full of several clichés."

"[23] In Moure's reviews of further episodes, he comments on how the series remains entertaining, "developing into a solid show," and that "watching Kouichi struggle to cope with the power that's been presented to him is becoming interesting.