Megalobox

By the end of the 21st century, boxing has become a sport fought in mechanical exoskeletons called Gear. Junk Dog, a man with no citizenship who throws fixed matches in the underground rings of the slums, meets the reigning champion Yuri and decides to fight his way into Megalonia, the tournament that crowns the best there is. With a forged identity and a new name, Joe, he sets out to climb from nothing to the top in three months, and to do it wearing no gear at all.