Ultraman: Survival Evolution

Beneath a gloomy gray sky lies a world in chaos, overrun by countless monsters. Humanity's living space has been relentlessly squeezed, and people spend every day in constant fear. In the wilderness, a lone boy staggers forward, swinging his fists at monsters for the sake of his future. The boy looks up at the sky and charges ahead with all his might. (The male protagonist of this novel can transform into a hybrid beast.)