Karasu Bank operates an exclusive underground casino where gamblersstake fortunes and lives in high-risk games. The Special Operations Department's Section 2 devises increasingly lethal gambling scenarios—higher ranks yield greater rewards but impose deadlier penalties. At the apex lies "1 Head", where defeat means certain death, followed by "1/2 Life", offering only marginal survival odds. The bank's Section 5 secures funding by inviting wealthy patrons to spectate. These sponsors finance the extravagant prizes while reveling in the spectacle of desperate players gambling with their lives.