Heart Gear manga volume 2 features story and art by Tsuyoshi Takaki.

Following the advice of new friends, Roue and Chrome set off to find Heaven Land, a gear utopia, in order to revive Uncle Zett. But when a threatening gear blocks their path, Chrome unknowingly takes on a vicious combat form that frightens Roue. What other secrets might Chrome have that he doesn’t even know himself? And when their next lead on Heaven Land brings them to Valhalla, a coliseum of warriors, will Chrome be forced to activate his combat form once more?