In a modern age where a colossal tower that pierces far beyond the Kármán line—a dungeon named “Tengoku” (Celestial Prison)—has appeared.

In Japan, it has become possible to make a living by relying on one’s own strength by wielding “Maken,” swords that harbor demonic power.

While many young people aspire to become “Makenshi” (Demonic Swordsmen), Jinya Kocho, who holds no particular interest and diligently works a part-time job for a shady employer, obtains a Maken by chance one day and becomes one himself.

Jinya defeats the monsters of Tengoku, seizes their power, and enhances both his Maken and himself.

As he does, he gradually comes to learn two things:

The peculiar nature of his own Maken—and the reason the monsters bear the names of angels…