Kings are individuals who have been bestowed with incredible supernatural powers and granted the ability to recruit others into their clans. Protecting the lives and honor of their clansmen is an integral part of the Kings' duties. After a video depicting the heinous murder of a Red Clansman spreads virally, the unassuming student Yashiro Isana is accused of homicide. Now, a manhunt is underway for his head, bringing him into contact with the infamous Black Dog Kurou Yatogami—a skilled swordsman and martial artist determined to follow the wishes of his late master, the Seventh King. Meanwhile, the current Red King, Mikoto Suou, faces his own imminent demise as the search for Yashiro narrows. But during Yashiro's struggle to prove his innocence, a greater conspiracy is unraveling behind the scenes; clouds begin to appear in his memory, and close friends start to question his very existence. What began as a simple murder is now leading towards a full blown war between Kings with the very fate of the world at stake.

Aslan Jade Callenreese, known as Ash Lynx, was a runaway picked off the streets of New York City and raised by the infamous godfather of the mafia, Dino Golzine. Now 17 years old and the boss of his own gang, Ash begins investigating the mysterious Banana Fish—the same two words his older brother, Griffin, has muttered since his return from the Iraq War. However, his inquiries are hindered when Dino sends his men after Ash at an underground bar he uses as a hideout. At the bar, Skip, Ash's friend, introduces him to Shunichi Ibe and his assistant, Eiji Okumura, who are Japanese photographers reporting on American street gangs. However, their conversation is interrupted when Shorter Wong, one of Ash's allies, calls to warn him about Dino. Soon, Dino's men storm the bar, and in the ensuing chaos kidnap Skip and Eiji. Now, Ash must find a way to rescue them and continue his investigation into Banana Fish, but will his history with the mafia prevent him from succeeding?

Guts, a man who will one day be known as the Black Swordsman, is a young traveling mercenary characterized by the large greatsword he carries. He accepts jobs that offer the most money, but he never stays with one group for long—until he encounters the Band of the Falcon. Ambushed after completing a job, Guts crushes many of its members in combat. Griffith, The Band of the Falcon's leader and founder, takes an interest in Guts and duels him. While the others are no match for Guts, Griffith defeats him in one blow. Incapacitated and taken into the Band of the Falcon's camp to recover, Guts wakes up two days later. He confronts Griffith, and the two duel yet again, only this time with a condition: Guts will join the Band of the Falcon if he loses. Due to his fresh injuries, Guts loses the fight and is inducted by Griffith. In three years' time, Guts has become one of the Band of the Falcon's commanders. On the battlefield, his combat prowess is second only to Griffith as he takes on large groups of enemies all on his own. With Guts' immense strength and Griffith's leadership, the Band of the Falcon dominate every battle they partake in. But something menacing lurks in the shadows, threatening to change Guts' life forever.

When Keyaru acquired his powers as a Hero who specialized in healing all injuries regardless of severity, it seemed that he would walk the path to a great future. But what awaited him instead was great agony; he was subjected to years of seemingly endless hellish torture and abuse. Keyaru's healing skills allowed him to secretly collect the memories and abilities of those he treated, gradually making him stronger than anyone else. But by the time he reached his full potential, it was far too late—he had already lost everything. Determined to put his life back on track, Keyaru decided to unleash a powerful healing spell that rewound the entire world back to the time before he began to suffer his horrible fate. Equipped with the anguish of his past, he vows to redo everything in order to fulfill a new purpose—to exact revenge upon those who have wronged him.