Requiem is the twenty fifth episode of Season 4 of the Teenage Mutant Ninja Turtles (2012 TV Series). This episode was directed by TBA and written by TBA. This episode will be aired on February 19, 2017.
- Shinigami was able to place trackers on two Elite Foot Bots (according to Karai) and tracked Shredder's Mansion north from New York City.
- Super Shredder's mutated heart is no longer his weakness, which is seen when Karai attempted to stab it with her Shikomizue but failed when the blade of the sword broke when it collided with the heart.
- The Super Mutagen was finally perfected by Baxter Fly. This was something he had been working on ever since Super Shredder retreated to his mansion at the end of Darkest Plight with side effects from the unstable Super Mutagen.
- When Super Shredder invades the Mutanimals Lair and sets fire to the whole lair, the scenery parallels to the fight that happened in the Hamato Dojo between him and Hamato Yoshi years ago.
- Leonardo, Donatello, Michelangelo, and Leatherhead fight against Rahzar, Fishface, Bebop, and Rocksteady at Coney Island, which is theme park that was first seen in The Pig and the Rhino. This is also the place where the Ninja Turtles, April O'Neil, and Casey Jones first fought Bebop and Rocksteady, as well as the place that Serpent Karai was hiding at.
- Also when Leonardo, Donatello, Michelangelo, and Leatherhead entered Coney Island and the merry-go-round turned on, Bebop shouts out "Turtles come out and play!", which was a line that he shouted out in The Pig and the Rhino as well. Even Bebop pointed out if the Ninja Turtles remembered when he said the line before.
- Splinter, Raphael, April O'Neil, and Slash fought Super Shredder at the rooftop of Wolf Hotel, a five star hotel that was first seen in The Gauntlet.
- Splinter is killed by Super Shredder with his steel claws, which parallels to Annihilation: Earth! Part Two when Shredder had also done the same thing with Splinter.
- When the Ninja Turtles are surrounding the corpse of Splinter, they all have flashbacks about him. But only three of them are scenes from previous episodes.
- The flashback that Raphael had was of him and Splinter in The Kitchen speaking about his anger issues, which is from Turtle Temper.
- The flashback that Donatello had was of him and the Ninja Turtles showing Splinter through the T-Phone that they fixed their existence from being known in the surface, which is from The Noxious Avenger.
- The flashback that Michelangelo had was of him stopping the blow that Splinter was going to give him while listening to music to show Donatello how to fight without thinking, which is from Monkey Brains.
- Super Shredder becomes much more enhanced in strength thanks to the doses of Super Mutagen given to him by Baxter Fly. Also Super Shredder no longer has feelings for Karai and wants everyone dead on his path.
- The Ninja Turtles, April O'Neil, and Casey Jones watch the series finale of Chris Bradford's 2 Ruff Krew.
- Karai gets badly hurt by Super Shredder and ends up in a hospital.
- Leatherhead drowns Rahzar in the ocean to his death at Coney Island.
- When Casey Jones is thrown from the rooftop of Wolf Hotel, his hockey mask breaks when he slams his face on a garbage truck.
- Super Shredder kills Splinter when he stabs him with his steel claws.
- Lil' Rineo/ Evil Ninja Commander's transformation is nearly identical to a giant version of Carter's mutation.
- Leonardo giving Karai CPR parallels the same action taken during Teenage Mutant Ninja Turtles III, Where he gave Yoshi CPR.
- When Leonardo, Donatello, Michelangelo, and Leatherhead entered Coney Island and the merry-go-round turned on, Bebop says "Turtles come out and play!", which is a reference to the film The Warriors.
- When Splinter trips Super Shredder with the rope in his cane and causes him to fall from Wolf Hotel, it is similar to the scene from the original TMNT film in which Splinter defeats Shredder the same way, only difference was that he used one of the Nun-Chucks of Michelangelo.
- Casey's crushing of Super Shredder in the garbage truck after a fall from a rooftop parallels the same action taken at the end of Teenage Mutant Ninja Turtles (1990 film) - complete with saying "oops", although he is far less jovial when doing so here, due to the circumstances.
- The way Super Shredder survives and breaks free of the garbage truck is similar to how Utrom Shredder survives and breaks free of the water tower dropped on him by Splinter in The Shredder Strikes, Part 2.
- When Super Shredder's hand emerges from the garbage truck, it is a reference to Teenage Mutant Ninja Turtles II: The Secret of the Ooze when Super Shredder's hand emerges from the remains of the destroyed docks.
- Through out the whole episode, Leatherhead for some unknown reason is shown with green skin and the same scars he had in Season 1.
- "Requiem" is a Catholic mass meant to honor the recently deceased, which is fitting for the episode's tragic ending.
- This episode aired earlier on December 30th, 2016 in South Korea.