KENGAN ASHURA Part I

Since the Edo periods of Japan, gladiator arenas exist in certain areas. In these arenas, wealthy business owners and merchants hire gladiators to fight in unarmed combat where winner takes all. Toki Taouma, nicknamed "Ashura", joins these arenas and devastates his opponents. His spectacular ability to crush his enemies catches the attention of the big business owners, including the Nogi Group chairman, Nogi Hideki. (Source: MangaHelpers)

Fist of the North Star

Nuclear war has devastated the planet, turning one fertile ground into a barren, inhospitable landscape on which mankind struggles desperately to stay alive. Society has collapsed and a fight for control wages between vicious dictators, super-powerful mutants, and biker gangs that terrorize the streets. In a world so cruel and bleak, only the chosen one can restore civilization to its former self. Kenshiro - master of the Hokuto Shinken fighting technique; a martial art so awesomely brutal that only a single being can be entrusted with its full power! (Source: Manga Entertainment)

Fist of the North Star 2

In the second series after Raoh has been defeated by Kenshiro a new rival appears. The Gentou Kouken warriors. Falco the successor of the Gentou Kouken takes orders from an evil ruler by the name of Jacko. He claims to be the man chosen by the Tentei and issues orders to his subordinates to capture anyone living in order to build up his Imperial Capital. Kenshiro once again rises out of the shadows and puts an end to his tyrannical ways. Amidst the mayhem Lynn gets captured and gets taken to the land of the Shura where only ruthless fighters exist. Now Kenshiro must pursue the captor and defeat the 3 Rasho of the land in order to escape with his life and with Lynn.

Megalobox

"To be quiet and do as you're told, that's the cowardly choice." These are the words of Junk Dog, an underground fighter of Megalo Box, an evolution of boxing that utilizes mechanical limbs known as Gear to enhance the speed and power of its users. Despite the young man's brimming potential as a boxer, the illegal nature of his participation forces him to make a living off of throwing matches as dictated by his boss Gansaku Nanbu. However, this all changes when the Megalo Box champion Yuuri enters his shabby ring under the guise of just another challenger. Taken out in a single round, Junk Dog is left with a challenge: "If you're serious about fighting me again, then fight your way up to me and my ring." Filled with overwhelming excitement and backed by the criminal syndicate responsible for his thrown matches, Junk Dog enters Megalonia: a world-spanning tournament that will decide the strongest Megalo Boxer of them all. Having no name of his own, he takes on the moniker of "Joe" as he begins his climb from the very bottom of the ranked list of fighters. With only three months left to qualify, Joe must face off against opponents the likes of which he has never fought in order to meet the challenge of his rival. (Source: MAL Rewrite)