In Tokyo in the near future, humans have discovered the fragments of the "Reincarnation Technique" (derived from "Mini Tensei" and "Makai Reincarnation"), and are trying to break through the boundaries of life and death through gene editing (Chimera), mechanical transformation (Ghost Soldiers), and soul sacrifice (Teten Doji's secret technique). But this blasphemy triggered "boundary leakage":
- The "Stigmata Angels" in heaven were corrupted by human greed (the corrupted setting of "Angel Sanctuary") and turned into killers with thorns and wings on their backs;
- The "Bone Hell Demon" in the demonic world crawls out along the energy cracks of the reincarnation technique and uses living people as "reincarnation containers";
- The human-made Chimera (a sutured body of beast + human + machine) and the Ghost Soldier (transformed into a semi-mechanical "living weapon") had their souls torn apart and began to devour flesh and blood indiscriminately.
What maintains the final balance are two types of "rule enforcers":
- The Dark Judge: Wearing a "judgment mask" engraved with ancient incantations, he has the power to judge "those who cross the line" (including fallen angels, out-of-control creations, and humans who abuse reincarnation), but every judgment will corrode his own soul (similar to the fateful curse of "Onikimaru");
- Biochemical hunters: Bounty hunters who wander in the "locked area" (the ruins with the most serious boundary leakage), make a living by hunting down Chimeras and recycling the cores of ghost soldiers. Their weapons are often "knives polished with demon bones" or "guns modified from angel feathers" (a mix of the weapon settings of "Onikimaru" and the violent aesthetics of AD SWAT).
