Megalobox

The protagonist of the story is a young man with no origin and known only by his ring name: “JNK.DOG”.

He survives by fighting in rigged, underground matches of a sport called Megalobox, a form of fighting utilizing powered exoskeletons.
JD is bored, resigned and unfulfilled—until the day he encounters Yuri, the reigning champion of the official Megalobox sport.