Radiation Revenant originated from a containment breach in the laboratory's nuclear research wing, where a scientist exposed to lethal radiation levels refused to die and instead reanimated as a corrupted entity. Prolonged interaction with mutagenic compounds fused its consciousness with the radioactive environment, turning it into a vengeful specter bound eternally to the spreading contamination.

Radiation Revenant possesses a semi-corporeal form that flickers between solid and ethereal states, allowing it to phase through obstacles and emit low-level radiation that corrodes nearby materials. It exhibits heightened resilience to physical damage due to its radioactive composition, and its presence causes electrical interference and biological decay in its vicinity. The entity can manipulate radioactive energy to create hazardous zones, and it is drawn to sources of contamination, making it a mobile environmental threat.

Radiation Revenant influences events by patrolling key areas of the course, forcing players to alter their routes and strategies to avoid its radioactive aura. It actively spreads contamination by triggering secondary spills and mutations, escalating the laboratory's collapse.