There are four variants of the original Carnifex, which are:
- Thornback - The thornback bears genetic enhancements that resemble large spikes or thorns, and are commonly used to breach enemy lines.
- Screamer-Killer - Screamer-Killers are easily identified by the piercing shriek that got it the "Screamer" part of its name. This scream is a warning for attackers that the Screamer-Killer is about to launch a blast of Bio-Plasma.
- Bile Beast - The Bile Beast spews acidic fluids onto its foes before attacking in close combat using its huge crab-like claws.
- Stone-Crusher - The Stone-Crusher is a siege variant of the carnifex. Armed with huge crushing claws, capable of tearing down the thickest walls, a massive scything tail and battering rams, it is used for crashing into enemy ranks and fortresses.
In addition, there is a powerful Carnifex wandering the universe by the name of Old One Eye, infamous for having survived many battles thanks to its ability to regenerate from most wounds, something a normal Carnifex cannot do. This beast has also displayed the ability to operate - and actually command swarms of “orphaned” Tyranids from well outside the reach of the Hive Mind, something which has caused those who know of it great concern.