Big Construction

Two days after A-City is leveled, a Hero Association staffer outlines a grand plan to enlarge the headquarters and lay down highways for rapid travel, a job he figures should take a decade and, being beyond ordinary means, has had its entire budget handed to a single individual. A tremor interrupts him, and a panicked colleague rushes in with a warning. Camera feeds reveal a four-legged machine as tall as the headquarters itself striding closer, so the staff summon the nearest heroes, the Tank Topper Army, who happen to be training in the association gym.

Before the alert reaches them, Tanktop Master tells his followers that losing to Tatsumaki in raw strength has only pushed him to train harder and squeeze out still more Tanktop Power.

Sent outside, the Tank Toppers are stunned by the machine's scale, and their leader charges in to try to halt it. The device spits out small orb-shaped drones that most of the team cannot handle, though Tanktop Master manages to smash them. The drones ignore the heroes entirely and start devouring the rubble left from A-City's ruin. A voice then issues from the machine, and Tanktop Master recognizes it as Metal Knight, who explains he was commissioned to rebuild the headquarters and expects to finish within ten days.

Grasping the sheer scope of the undertaking, Tanktop Master counts it as yet another loss for himself.

This extra ran with Volume 7, dated February 22, 2015, across eighteen pages. Afterward Tanktop Master trains even more fiercely, stung by defeats at the hands of both machines and psychic power, while association staff grow uneasy with Metal Knight's methods and begin viewing him as a threat. The project once estimated at ten years is completed in only seven days.