With Splinter dead and Karai in the hospital, the Turtles mount a final offensive on Super Shredder's lair to end his menace once and for all.
- Armor-Piercing Question: Leo gives one to Shredder during the final showdown, while calling him out for Splinter's murder. Hearing it actually gets Shredder to hesitate for a few minutes.Leo: You killed him! He was your brother, and you KILLED HIM! He was your brother, Saki! Your best friend! How could you do that?!
Shredder: Splinter was cursed to become a loathsome rat! It was his fate, his destiny!
Leo: You're a monster! A DEMON! Is that your destiny?!
Shredder: No... I... I... - Ascend to a Higher Plane of Existence: Splinter appears to Leonardo as a spirit after his funeral, telling him he has attained a higher spiritual plane of existence. In a rather unique example, he implies this is what happens to everyone that dies.Splinter: Passing into death, we merge with the whole of life. We become one in all of nature. In all of the universe. Even with you.
- Battle Amongst the Flames: Again, Shredder fights while a fire is going on. This time, he sets his house on fire to deter the Turtles, but they fight him on top of his burning house.
- Beyond Redemption: In the past, Splinter had offered Shredder multiple chances to give up his revenge quest and redeem himself. But after Shredder killed him in the previous episode, the Hamato Clan and their allies (and Splinter's spirit) now conclude that Shredder is beyond saving and needs to be put down stop his reign of terror for good. As if to hammer down the point, the retromutagen fails to work on the Super Shredder, symbolizing that he's become a true demon incapable of reverting back to a normal human.Splinter: Shredder is still alive. You must end this, Leonardo.
- Bilingual Bonus: Owari means "The End" in Japanese. This episode concludes the "City at War" arc, and with Leonardo killing Shredder, it symbolizes not only his death, but the end of the feud between the Hamato Clan and the Foot Clan.
- Bittersweet Ending: The Turtles and their allies managed to kill Super Shredder and defeat most of the Foot clan (For now), but at the cost of Master Splinter's life. That said, it's still a far happier ending than the last two seasons.
- Bow and Sword in Accord: Leo arms himself with a bow along with his katana.
- Brought Down to Normal: Stockman is turned back to normal, not that he's happy about it since being a mutant fly made him smarter and stronger.
- The Bus Came Back: We see virtually all of the Turtles' allies for Master Splinter's funeral (Unfortunately, due to her being injured and in the hospital, Karai couldn't be there). Special mention to Pigeon Pete and Kirby O'Neil, even Dr. Cluckingsworth is there.
- Call-Back: Splinter's burial site is April's family's farm.
- The Cameo: The Turtles' allies attend Splinter's funeral, and aren't seen for the rest of the episode.
- Darker and Edgier: About as much as the previous episode, if not more. The war reaches its climax as Raph takes apart Xever's gear and leaves him to asphyxiate on shore. Followed by Donnie hacking the Foot Clan's training equipment and using it on Bebop and Rocksteady. And of course, Leonardo killing the Super Shredder.
- Death Trap: Bebop and Rocksteady turn their training room up to eleven to create one for the turtles.
- Decapitation Presentation: As a G-rated version, Leo emerges from fighting with Shredder holding the mutated Kuro Kabuto. How he would have gotten it off is better left ignored.
- Disney Death: Bebop and Rocksteady are seemingly killed by their training room's defenses, Xever is passively left without his legs or rebreather on shore, and Stockman is left unconscious in Shredder's house while Shredder sets it on fire.
- Due to the Dead: The episode opens with the Turtles and all of their allies attending Splinter's funeral.
- Dwindling Party: During the final battle with Shredder, the Hamato Clan is knocked off the roof one by one until only Leo is left.
- Earn Your Happy Ending: The turtles have spent a few seasons of their lives fighting assassins and aliens and the like. Although they recently lost Splinter along the way, the death of Shredder hails a new, peaceful chapter in their lives. Not to say they don't welcome any potential adventures in the near-future.
- Fed to the Beast: Tiger Claw uses a Trap Door to drop the protagonists into a pit of hungry tigers.
- Grand Finale: For the "City at War" arc and the fourth season.
- According to Brandon Auman, this episode is the true series finale, and that the season 5 episodes are all just side stories.
- Even the Kavaxas arc of the fifth season can be considered this.
- Hope Spot: Leo tries appealing to any sense of decency Shredder has, asking him if his destiny was to become a demon. Shredder hesitates at this, but Leo attacks him, revealing it to have been a ploy.
- Ignored Epiphany: After Leo called out the Shredder on his hypocrisy and his transformation into a literal monster, Shredder actually hesitates in his reply, as if the last shred of humanity inside him is just realizing what he has become. But Leo isn't interested in redemption for Shredder and exploits that hesitation for a sneak attack, which causes Shredder to dismiss these self-doubts in favor of killing Splinter's chosen successor.
- I Just Want to Be Special: Baxter Stockman actually enjoyed being a mutant housefly, and is upset when he's Brought Down to Normal. At least they didn't kill him.
- Imperial Stormtrooper Marksmanship Academy: The training room's lasers only when targeting the turtles. Averted when Donnie hacks them and we get a Gory Discretion Shot as they continue firing on Bebop and Rocksteady even after they stop screaming. The two aren't mentioned at the end when the protagonists talk about Tiger Claw still being out there.
- Kill It with Fire:
- When Super Shredder appears, he throws Molotov Cocktails that set his mansion on fire and separate the Turtles from April and Casey, leaving them to face Shredder alone on the roof. The fire also prevents Donnie from rejoining the fight when he gets knocked off the roof.
- Killed Off for Real:
- The heroes finish burying Master Splinter, reminding the audience that he is dead with no way to come back.
- By the end of the episode, Shredder is killed once and for all.
- Lock-and-Load Montage: The Turtles, April, and Casey all get one, Casey making a new hockey mask, Donnie preparing retromutagen to use on Shredder, Leo arming himself with a bow and arrows, and the Turtles all dressing in black masks and war paint.
- Murder by Inaction: Raph breaks Xever's robotic legs and rips off his gill respirator, then leaves him to flop helplessly on the shoreline.
- Mythology Gag:
- The manner in which Shredder dies, decapitation, resembles his second death in the original comics and one of the attempts to kill him in the 2003 series.
- Leo and Shredder's final battle taking place on a rooftop alludes to their showdown in issue #21 of the Mirage comic.
- Nice Job Breaking It, Hero: Mikey using one of the vials of retromutagen to turn Stockman back to normal when it was meant for Shredder. Subverted in that the other one had no effect on Shredder at all, indicating he was too mutated (or the retromutagen wasn't strong enough) to do so. They also don't need the retromutagen to defeat the Shredder outright.
- Off with His Head!: Leonardo finally defeats and kills the Super Shredder by slicing off his head. No blood is seen around Shredder's neck, but a discretion shot of blood flying off of Leo's sword can be seen after Leo strikes. He tosses his helmet to prove the deed is done.
- Relative Button: During their fight, Tiger Claw takes the time to mock Splinter's death to Leo's face ("Do you feel it, boy? The weight of the world crushing you, now that your sensei is gone?!"). Leo promptly snaps and lops off Tiger Claw's robotic arm.
- Roaring Rampage of Revenge: The Turtles, April, and Casey are tasked by Splinter's spirit to kill Shredder and end the Hamato-Foot clan war once and for all. The group has no mercy for the Foot Clan members in their way.
- Rooftop Confrontation: The climatic battle takes place on the rooftop of Shredder's hideout as it burns.
- Run the Gauntlet: To get to Shredder, the Turtle family has to fight their way through his base, taking out all of his henchmen on the way: Xever, Baxter Stockman, Bebop, Rocksteady and Tiger Claw. Only Rahzar is missing, as Leatherhead drowned him in the last episode.
- Shut Up, Hannibal!: Raph pulls one off against Fishface:Fishface: You think you have the best of me?! You are nothing, Raphae-
[Raph punches him out] - Swiss-Army Appendage: Tiger Claw got a robotic arm with interchangeable, specialized hands to replace the arm Alopex cut off.
- Sympathy for the Devil: Mikey chooses to spare Stockman in their Roaring Rampage of Revenge, stealing one of the doses of retromutagen meant for Shredder and using it on him. Stockman still gets knocked unconscious for being an Ungrateful Bastard, but compared to the fates of his allies...
- The Gloves Come Off: The Turtles do this, having every intent of flat out killing Shredder. With the exception of Stockman, they extend this to the rest of the Foot Clan, as the Turtles outright attempt to kill their opponents. Given Shredder killed their father the previous episode, it's not hard to see why.
- Wham Episode: The feud between the Hamato and Foot clans end with Leonardo killing Oroku Saki, the Super Shredder.
- What Happened to the Mouse?: Baxter is not seen or heard from ever again in the show after he was knocked out by Mikey in this episode.
- What the Hell, Hero?: Donny gives Mikey an earful for using one of his retromutagen vials on Stockman when they were reserved for Shredder. Of course, since Shredder No Selled the retromutagen anyway, it was better to have it be used than wasted.
- You Just Had to Say It: After defeating a group of Footbots:Mikey: These things are a slice of cake and a piece of pie! Mmm... so hungry.
Raph: Yeah! At this rate, we've got no problemo!
[cue the Elite Footbots]
Donnie: One of us had to say something, didn't they? - You Monster!: Leo calls Shredder this in their duel.
- You Will Be Spared: While the Turtles attack the Foot headquarters with every intent to outright kill all in their way, the one exception is Stockman, since they know that of all of the Shredder’s conscripts, he is the one who lost most of his sanity in the process and was not outright evil. They come with a dose of retro-mutagen to turn him back into a human and make no further attempt to attack him afterwards.
