The World Is Mine

The World Is Mine (ザ・ワールド・イズ・マイン) is a manga series by Hideki Arai. It was serialized in Young Sunday.

Plot
Meet Mon, a violent killer faithful only to his own eruptive desires, and his timid companion Toshi, a demolition-devil with a fanatical thirst for destruction. Their killing-spree across Japan is destined to intersect the path of the enormous "Higumadon", a mysterious beast on a Godzilla-like rampage from Hokkaido to Tokyo.