- A cunning mutant who acquired new technologies, the Assassin has grenades which disrupt the position of his enemies
Assassin is the smallest mutant available. Its special mutation ability is throwing technology grenades (Assassin Grenade), which sends out high pressure blast of air making its victims fly in different directions! It is also faster than the Slug Mutant. Overall it is a very good mutant to disillusion soldiers and push soldiers out of camping positions. Some people consider this character as cheap due to its special making it easy to knocked back from a position.
Assassin's [G Skill] is the Assassin Grenade that can blast people through walls or even above/below its explosion range. If the soldiers are hiding in a place that the grenade can't get behind them, you can simply throw it above or below that position. But its Left-click and Right-click attacks can be a bit difficult than the others, since it requires much more precise timing. It's recommended that you purchase the Mutation Spike or Nano Hook-Devil to work with Assassin.
- The Assassin has a normal view heigh just like the other mutant, reguarding that it should have a lower view because of its real height
- In CF Vietnam, Assassin is called "Tia chớp đen" (Black Lightning), based on his look on Titan level, though the HUD still displays its name correctly (Assassin).
- Assassin is very unpopular in maps such as Merida, Zone 13, and Seaside Hotel, because he can easily disrupt soldier's defense position, which leads many players to vote kick Assassin player or simply quit and go play at another room.
- Due to its short height, it will be harder to hit by Commando, Nemesis and Devil Hunter.
- Despite its tricky attacks, Assassin gains an incredibly fast striking speed when equipped with the Mutation Spike or Nano Hook-Devil. That, combined with the mutant's own agileness and short height, make Assassin an extremely deadly force to be reckoned with, being as dangerous as or even more than Xeno/Havoc and Maiden.
- CF Indonesia is the only version that offers this mutant character permanently from an event capsule.