Linebarrel stands as a towering, imposing figure, embodied in Sentinel's RIOBOT line with a rugged, industrial aesthetic. The silhouette is a well-balanced mix of armor plates, exposed joints, and integrated thrusters that convey speed and power even in stillness. The surface finish contrasts matte armor panels with glossy accents to highlight edges and vents, while visible rivets and panel lines emphasize its engineering origins. The head design features a prominent central crest and sensor arrays that convey intelligence. Articulation is engineered for dramatic action poses, with multiple hands and optional weapons available. The overall presentation communicates raw, heroic power ready to defend or devastate depending on the pilot's will.

Within the Kurogane no Linebarrels universe, Linebarrel becomes more than a machine after it fuses with its chosen pilot, unlocking a battlefield power that tests trust and restraint. The story follows a young protagonist drawn into a covert conflict between powerful organizations and rival pilots who crave control of Linebarrel's overwhelming capabilities. As battles unfold, relationships are strained - friends become enemies, and loyalty is questioned. Linebarrel's enhanced cognition and armor growth mirror the pilot's inner development, forcing difficult choices about sacrifice, responsibility, and what it means to wield a weapon that can reshape cities. Through trials, the pilot discovers that true strength lies not just in firepower, but in protecting the innocent while avoiding reckless conquest.