TMNT’s Original Fifth Turtle Is Way Darker Than Their Newest Recruit

screenrant.com:

Since the Teenage Mutant Ninja Turtles’ found new life with IDW Publishing, the team has added a fifth Turtle, Jennika, into their ranks, but this isn’t the first time within the franchise another mutant turtle has been introduced. The original Fifth Turtle was much darker than TMNT’s newest recruit, as the first one turned out to be a brutal villain who ignored the Turtles' cry for peace instead of seeing the light and joining the team as Jennika does.

In Teenage Mutant Ninja Turtles#15 by Kevin Eastman, Tom Waltz, and Andy Kuhn, the scientists who were responsible for turning the Turtles into humanoid mutants are working on doing the same thing to another turtle in their lab but with a diluted sample of the mutagenic serum. The result is a highly aggressive mutant turtle named Slash who makes it his main goal to find and destroy his TMNT brothers. 

Related: TMNT’s Darkest Hero Is More Like Daredevil Than Fans Realize

The first time Slash sees the Teenage Mutant Ninja Turtles, it is after they take down a gang of street thugs then run away silently into the night. Slash looks upon their work with admiration and even rips off a piece of one of the unconscious thugs' black shirts and fashions himself a mask just like his brothers. While it seems as though Slash would be willing to join the Turtles, he later proves the opposite is true. When Slash finally tracks down the Turtles, he corners them and uses his superior strength to bring them to the brink of death. Leonardo tries to talk sense into Slash, but the brute won’t hear it as he is just too far gone to be persuaded to join his turtle brethren. 

Slash is a much darker Fifth Turtle than the current one, Jennika, with almost the exact opposite origin story. Slash was a