| Abbreviation | Definition |
|---|---|
| CGF | Clan of Godlike Fraggers |
| CHILD | Cybernetic Human Interface Lifeform Device |
| CHUD | Cannibalistic Humanoid Underground Dweller |
| CI | Carnage, Inc. |
| CIA | Celestial Intervention Agency |
| CIA | Committee to Intervene Anywhere |
| CIS | Confederacy of Independent Systems |
| CK | Celestial Kingdom |
| CK | Combat King |
| CK | Commander Kid |
| CLAUDIO | Cybernetic Lifelike Android Used for Dialogue Interaction and Observation |
| CLUB | Clandestine League Unified by Borock |
| CM | CyberMonster |
| CMF | Clan Mortal Fury |
| CMI | Confederation Military Intelligence |
| CMP | Confused Mass of Protoplasm |
| CMTR | Certified Material Test Report FOR wHOOM, wHAT wHEN, wHER, wHY AND wHOM sez? |
| COBRA | Covert Operational Bureaucratic Revolutionary Army |
| COD | Chaplain Of Darkness |
| COD | Children Of Destiny |