Fear, survival, instinct. Thrown into a foreign land with nothing but hazy memories and the knowledge of their name, they can feel only these three emotions resonating deep within their souls. A group of strangers is given no other choice than to accept the only paying job in this game-like world—the role of a soldier in the Reserve Army—and eliminate anything that threatens the peace in their new world, Grimgar. When all of the stronger candidates join together, those left behind must create a party together to survive: Manato, a charismatic leader and priest; Haruhiro, a nervous thief; Yume, a cheerful hunter; Shihoru, a shy mage; Moguzo, a kind warrior; and Ranta, a rowdy dark knight. Despite its resemblance to one, this is no game—there are no redos or respawns; it is kill or be killed. It is now up to this ragtag group of unlikely fighters to survive together in a world where life and death are separated only by a fine line.

Reeling from her recent breakup, Momo Ayase, a popular high schooler, shows kindness to her socially awkward schoolmate, Ken Takakura, by standing up to his bullies. Ken misunderstands her intentions, believing he has made a new friend who shares his obsession with aliens and UFOs. However, Momo's own eccentric occult beliefs lie in the supernatural realm; she thinks aliens do not exist. A rivalry quickly brews as each becomes determined to prove the other wrong. Despite their initial clash over their opposing beliefs, Momo and Ken form an unexpected but intimate friendship, a bond forged in a series of supernatural battles and bizarre encounters with urban legends and paranormal entities. As both develop unique superhuman abilities, they learn to supplement each other's weaknesses, leading them to wonder if their newfound partnership may be about more than just survival.

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?