In the desolate wastelands of the Lost Ground, a mercenary named Kazuma scrapes by using his Alter power—a genetic mutation that allows him to coat his right arm in metallic armor. His reckless lifestyle catches the attention of HOLY, the elite police force tasked with capturing rogue Native Alters.
Kazuma comes face-to-face with Ryuho, a cold, calculating prodigy of HOLY who wields a terrifying humanoid Alter known as Zetsuei. A massive, deeply personal rivalry is instantly ignited as Ryuho effortlessly overpowers Kazuma and drags him to HOLY headquarters.
Imprisoned within HOLY's massive fortress, Kazuma realizes the sheer scale of the organization hunting him. He crosses paths with the sympathetic Mimori Kiryu and the impossibly fast, eccentric HOLY member Straight Cougar before launching a violent, one-man prison break.
Back in the wastelands, Kazuma takes a poorly-paying job from a young girl to protect her village from a rogue Alter user wielding a massive, artillery-style weapon. Kazuma proves that raw, unrefined power can still shatter military-grade hardware.
Mimori begins to investigate the dark, unspoken truths behind HOLY's methodology. She ventures into the Outer areas of the Lost Ground, encountering Kazuma and realizing that the Native Alters are not the mindless monsters the government propaganda claims they are.
HOLY cracks down hard on the Native Alters. Kazuma engages in a brutal, high-speed rematch against Ryuho and Zetsuei. The sheer force of their clashing Alter powers begins to cause strange, unstable gravitational anomalies in the surrounding area.
Desperate to prove his worth to Ryuho, young HOLY member Asuka Tachibana hunts Kazuma down using his Eternity Eight orb Alters. Kazuma brutally dismantles Asuka's naive worldview, teaching him a harsh lesson about what it takes to actually survive in the wastelands.
A sinister HOLY member named Unkei uses his reality-altering script powers to manipulate Kazuma's allies, forcing them to turn against him. Kazuma has to rely on pure instinct to break through the psychological warfare and smash the illusion.
Pushed to his absolute limits by escalating HOLY attacks, Kazuma's Alter undergoes a violent evolution. He unlocks the second form of the Shell Bullet, granting him a massive surge in power and a localized propeller capable of blinding speed.
Kazuma and his best friend Kimishima find themselves pinned down in a desperate, seemingly unwinnable shootout against a massive HOLY strike force. Straight Cougar unexpectedly intervenes, showcasing his incredible speed and highly questionable loyalties.
The origins of the Alter phenomenon and the catastrophic geological event that created the Lost Ground are explored. Tensions between the wealthy Inner city and the impoverished Outer settlements reach a violent boiling point.
A devastating turning point for the series. During a massive, chaotic raid by HOLY, Kimishima puts his life on the line to support Kazuma. The resulting tragedy permanently alters the trajectory of Kazuma's life, replacing his carefree attitude with pure, murderous vengeance.
Consumed by grief and absolute rage, Kazuma storms HOLY headquarters for a catastrophic, earth-shattering clash with Ryuho. Their combined, violently opposing powers tear open a massive dimensional rift, swallowing them both and devastating the landscape.
Eight months later. The Lost Ground has been completely subjugated by Kyouji Mujo, a tyrannical emissary from the Mainland. Kazuma and Ryuho are presumed dead, and young Kanami has been captured and forced into a brutal labor camp.
Ryuho, suffering from severe amnesia, is found living peacefully with a Native settlement. When Mujo's heavily armed Mainland forces attack the village, Ryuho is forced to rediscover his Alter and remember the warrior he used to be.
Kazuma is revealed to have survived, but he has become a feral, hollow shell fighting in illegal underground death matches. It takes a brutal confrontation with a Mainland assassin to reignite the fire in the Shell Bullet.
Kazuma crosses paths with Ayase, a Native Alter user who has been manipulated and blackmailed into hunting him for Mujo. The tragic reality of Mujo's absolute, insidious control over the Lost Ground's population is fully exposed.
Unable to stomach Mujo's tyranny, Straight Cougar officially rebels. He tracks down Kazuma for a blistering, high-speed clash, pushing Kazuma to evolve his Alter once more in preparation for the upcoming war.
Mujo dispatches the Tokonatsu Sisters—three bizarre, highly eccentric Alter users—to assassinate the heroes. The ensuing battle is an incredibly absurd, comedic breather episode right before the narrative plunges into the dark, heavy endgame.
Kanami's latent Alter power fully awakens, allowing her to telepathically "scry" and connect with Kazuma. Hearing her voice across the wasteland, Kazuma launches a desperate, high-speed rescue mission to pull her out of Mujo's labor camp.
Kazuma and Ryuho finally cross paths again. Instead of immediately trying to kill each other, the two bitter rivals realize they must temporarily unite their overwhelming powers to tear down Mujo's forces and reclaim their home.
The enigmatic commander of HOLY, Martin Zigmarl, finally reveals his true, terrifying Alter power. Ryuho engages his former mentor in a masterclass battle of ideals, proving his resolve to protect the Lost Ground on his own terms.
As Mujo's overwhelming forces corner the heroes, Scheris Adjani makes the ultimate sacrifice. She uses her healing Alter to completely restore Ryuho at the cost of her own life, dying in the arms of the man she loves.
Kazuma and Ryuho launch a full-scale, two-man apocalyptic assault on Mujo's fortress. Pushed past the absolute brink, Kazuma's Alter evolves into its final, ultimate form: the full-body armor known as Proud Fist.
The climactic battle. Kyouji Mujo absorbs a crystalline entity from the "Other Side," gaining god-like power. Kazuma and Ryuho unleash the absolute maximum potential of their Alters, shattering Mujo and saving the Lost Ground.