In a fantasy world where adventurers wield unique skills, Alkus is a member of an S-rank party called the Cruel Blade, also known as Brutal Edge. His skill, Slime, grants him two abilities: Mimicry, which lets him transform into a slime, and Division, which creates copies of himself. Both abilities are considered weak and useless in direct combat, making Alkus the party's designated pack mule and lookout. Despite his loyalty, the party leader Dan violently expels him, declaring him dead weight and violently humiliating him in public.

After the betrayal, Alkus stumbles upon the hidden potential of his skill. Each slime clone he creates multiplies the experience points he gains from defeating monsters, meaning the more copies he produces, the faster he levels up. What was once dismissed as a worthless ability becomes a cheat-level power multiplier. By hunting low-level slimes and stacking his experience gain, Alkus accelerates his growth exponentially, going from outcast to powerhouse at a speed no ordinary adventurer can match.

As he trains in solitude, Alkus discovers that his clones share his perception, making them ideal for scouting and coordinated attacks. He starts to accumulate strength with an eye toward confronting his former party and proving his worth to the world. Along the way, he encounters new allies and increasingly dangerous foes, developing his versatile slime abilities into a formidable combat style. His journey transforms him from a scorned underdog into a contender for the title of strongest adventurer, driven by a desire for retribution and a growing resolve to carve his own path in a world that once looked down on him.