10 MORE Star Trek Villains Who Killed The Most

Redjac appears in The Original Series episode Wolf In The Fold. A non-corporeal entity, it travels from planet to planet, via possession, committing murders for the simple pleasure of killing. It was during its tenure on Argelius II that it met its supposed downfall.

Redjac is an outlier on this list as it is not known for certain how many people it had killed. It was clearly hundreds of years old, as it was revealed to have been the infamous serial killer, Jack the Ripper, in the past. Traveling from planet to planet, it was responsible for murdering many women. Spock suggested this was because it enjoyed their fear more than the fear of men.

The episode saw Redjac take control of the Enterprise, though it was then forced back into Hengist's body, and was beamed into space. The expanded universe showed that it was not the end for this monster, as it latched onto another ship to survive, going dormant for a century before returning, this time to do battle with the Enterprise-D. It also appeared in the two-part comic Wolf On The Prowl and Wolf At The Door, where it was finally defeated.