Heavy Object

is a Japanese light novel series written by Kazuma Kamachi, with illustrations by Nagiryo. The series began publication on October 10, 2009 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
In the distant future, the nature of war has changed. "Objects"—massive, spherical tanks impermeable to standard weaponry and armed with destructive firepower—rule the battlefield; their very deployment ensures victory, rendering traditional armies useless. However, this new method of warfare is about to be turned on its head.

Qwenthur Barbotage, a student studying Object Design, and Havia Winchell, a radar analyst of noble birth, serve in the Legitimate Kingdom's 37th Mobile Maintenance Battalion, tasked with supporting the Baby Magnum, one of the nation's Objects. Unfortunately, a battle gone awry places the duo in a precarious situation: mere infantry stand face-to-face against the unfathomable might of an enemy Object. As they scramble to save themselves and their fellow soldiers, a glimmer of hope shines through, and the world's perception of Objects is changed forever.

Heavy Object follows these two soldiers alongside Milinda Brantini, the Baby Magnum's pilot, and their commanding officer Frolaytia Capistrano as the unit treks all over the globe to fight battle after battle. Facing one impossible situation after another, they must summon all their wit and courage to overcome the insurmountable foes that are Objects.

Characters

 * Qwenthur Barbotage
 * Havia Winchell
 * Frolaytia Capistrano
 * Milinda Brantini
 * Sladder Honeysuckle
 * Ayami Cherryblossom
 * Prizewell City Slicker
 * Lendy Farolito
 * Ohoho
 * Charlotte Zoom

The Circumstance Leading to a Simple Killer Princess's Marriage Was A Certain Magical Heavy Zashiki Warashi
A Crossover between Kazuma Kamachi's various light novel series including: 'A Certain Magical Index', 'Heavy Object', 'Zashiki Warashi of Intelli Village', 'Simple Series', 'The Circumstances Leading to Waltruate's Marriage' and 'Murder Princess and Deep End'

Heavy Object
The first manga adaptation of the light novel: with art by Shinsuke Inue. It was serialised in Dengeki Black Maoh and released under the Dengeki Comics imprint from May 2011.

Heavy Object S
The second manga adaptation of the light novel: with art by Sakae Saito. It was serialised in Dengeki Maoh and released under the Dengeki Comics imprint from August 2012.

Heavy Object A
The third manga adaptation of the light novel: with art by Sakae Saito. It was serialised in Dengeki Maoh and released under the Dengeki Comics imprint from September 2015.

Anime
An anime adaptation of the first three volumes of the light novel, produced by JCSTAFF, ran for 24 episodes between October 3, 2015 and March 26, 2016.
 * see: Heavy Object (Anime)