Teenage Mutant Ninja Turtles: The Last Ronin

Teenage Mutant Ninja Turtles: The Last Ronin is a five-issue comic book miniseries published by IDW Publishing. The series is written by Kevin Eastman and Tom Waltz, based on a story by Eastman and Peter Laird, and drawn by Esau and Isaac Escorza, Ben Bishop, and Eastman. The story follows characters from the Teenage Mutant Ninja Turtles franchise in an alternative future, wherein the last remaining turtle seeks to avenge the death of his brothers by killing the grandson of one of the Turtles' arch-enemies, the Shredder. Despite being published by IDW, it is unconnected to the IDW series' continuity and is set in its own universe, dubbed the "Roninverse".

The Last Ronin was followed by Teenage Mutant Ninja Turtles: The Last Ronin - Lost Years and Teenage Mutant Ninja Turtles: The Last Ronin II - Re-Evolution in 2023.

A video game is being developed by Black Forest Games and published by THQ Nordic for PS5, Xbox Series X/S, and PC. And a film adaptation are both in development.

Plot
In the future, New York City is ruled by Oroku Hiroto, grandson of the Shredder and son of Karai, running the city with meticulous fascism and totalitarianism. A lone turtle, haunted by hallucinations of his deceased brothers, works to end Hiroto, whom he blames for his brothers' deaths. He traverses through the now heavily guarded New York City, fighting against synthetic ninjas (dubbed Synjas) on his way to the Foot Clan headquarters. He crashes out of the building, having failed his mission, and retreats into the sewer as a teenage girl called Jones follows. She finds the turtle attempting seppuku before passing out from blood loss, and wakes up to see an older April O'Neil, who identifies the turtle as Michelangelo.

Flashback sequences in a sepia tone and in the style of the original Mirage comics reveal the events that led up to the present. After Shredder's death, the Turtles and the Foot Clan originally made a truce, which fell apart as Karai tried to end the conflict between their families once and for all. An ambush leaves Splinter severely injured, and an enraged Raphael confronts Karai in an attempt to kill her, but Raphael is stabbed in the neck and Karai is put in a coma from the fight. Baxter Stockman sends an ambush to retrieve Professor Honeycutt, which kills Leonardo and Casey Jones, and a deceitful peace meeting set up by the Foot Clan has Donatello and Splinter killed as well. Mikey left New York and lived in solitude for years, accompanied by Splinter's journal, but a fight with a gang makes him realize that it is his duty as the final remaining member of the Hamato family, the Ronin, to kill Hiroto.

Mikey catches up with April and meets her daughter, Casey Marie Jones, who is part of a small resistance movement and is training herself to fight the Foot Clan. As Mikey grapples with his feelings on the resistance movement, Casey Marie's inexperience, as well as his advancing mutation, Hiroto puts the entire city under Martial Law in order to wrestle more control over it, which forces Casey Marie to gather resistance forces to stage an assault on Baxter Stockman's Fortress to disable the technology used by the Foot Clan. April, Casey Marie, and Mikey get the remains of Professor Honeycutt to kill Stockman and send a power outage throughout the entire city.

The power outage causes a flood in the sewers that threatens to drown the resistance members and April. April reveals to Casey Marie that Casey is a mutant due to the former's extended exposure to the mutagen inside the turtles. While Casey Marie tries to stop the flooding and rescue her mother, Mikey confronts Hiroto, who kills Karai and is now equipped with a special metal suit, and they both engage in a battle. They both land in the city outskirts, where Hiroto electrocutes himself to death and mortally injures Mikey, where Casey Marie and April bid farewell as he dies. While Mikey reunites with his brothers, Casey Jones, and Splinter in the afterlife, Casey Marie begins raising a new generation of mutant turtles to train them in the ways of ninjitsu.

Development
In December 2019, it was teased that a new TMNT project, dubbed The Last Ronin, would begin publication in mid-2020. In April 2020 the series was properly announced, Kevin Eastman revealing the story was based on an old story outline written by Eastman and Peter Laird back in 1987, before he updated it with Tom Waltz. While Laird did not write the series, he is credited with the story behind it along with Eastman and Waltz. Andy Kuhn was set to be the original artist for the series, before being replaced with Esau and Isaac Escorza, with Ben Bishop joining the project to illustrate the flashback sequences.

The decision to make Michelangelo the last of the surviving turtles was made by Eastman and Waltz. When asked why Michelangelo was chosen by the writers, Waltz stated: "The simplest answer is that Mikey was the brother we figured nobody would expect. The happy-go-lucky party dude is now Rambo? What?! Raph seemed too obvious, Leo wasn't too far behind on the obvious scale, and Donnie seemed like someone who would've gone more tech than conventional in his revenge, and we really wanted this to be a grunt's story. [...] Plus, Kevin really liked the idea that Mikey, who was the first TMNT ever drawn, was also the last to be alive. Thematically, Mikey gave us the opportunity to explore the irony of the one person in the family who never truly bought into the clan-war aspect that exists at the foundation of their lives – being the only one left alive and stuck with the mission of ultimately winning said war, or dying trying."

Follow-ups
In July 2022, it was announced that a prequel/sequel, dubbed Teenage Mutant Ninja Turtles: The Last Ronin - Lost Years would release in 2023, and follow Michelangelo's training leading up to his confrontation with Hiroto inter spliced with Casey Marie Jones mentoring the next generation of Turtles (Odyn, Moja, Uno, and Yi). Eastman and Waltz would return to write, with S.L. Gallant serving as the primary illustrator and Ben Bishop drawing the flashfowards with Casey Marie. The series would begin publication in January 2023, before concluding in August that same year.

In July 2023, a sequel was announced, Teenage Mutant Ninja Turtles: The Last Ronin II - Re-Evolution, and will follow the events of The Last Ronin and The Lost Years as Odyn, Moja, Uno, and Yi protect the streets of New York with their sensei, Casey Marie Jones. Eastman and Waltz will return to write, along with the Escorza brothers and Ben Bishop drawing the series. The series began publication in March 2024.

Video game
A third-person action-RPG video game adaptation of The Last Ronin is in development by Black Forest Games, with THQ Nordic set to publish for PS5, Xbox Series X/S, and PC.

Film
A film adaptation of the graphic novel was announced to be in development by Paramount Pictures in April 2024. The film, produced by Walter Hamada and written by Tyler Burton Smith, will receive an R-rating and be live action.