Shelluva Boss
is a crossover fanfiction between Teenage Mutant Ninja Turtles and the Hellaverse, specifically focusing on the 2003 animated Turtles meeting the characters of Helluva Boss, written by lightyearpig that began in January 2024.
When I.M.P is hired to kill the Teenage Mutant Ninja Turtles, things sure do happen! Namely, their client happens to be the Shredder, who steals Stolas's grimoire to conquer both Hell and Earth, forcing the Immediate Murder Professionals to form an uneasy alliance with the Heroes in a Half Shell to stop Ch'rell, Oroku Saki and Kavaxas from enslaving the living and the dead.
The story can currently be found on FanFiction.Net and
Archive of Our Own.
Shelluva Boss contains examples of:
General trope examples:
- Actor Allusion: Blitzo voices his dislike of Katie Killjoy in Chapter 4 and he's not really sure why, though he believes it's something to do with her voice. Both characters just so happen to be voiced by Brandon Rogers.
- Adaptational Species Change:
- Anton and Owen are strongly implied to be their universe's equivalent to Bebop and Rocksteady. However, instead of being mutated into an anthropomorphic warthog and rhinoceros by the Shredder, they're instead turned into their respective animals when they enter Hell.
- Kavaxas is changed from a Demodragon in the 2012 animated series into a Sinner who Was Once a Man here.
- Jasper Barlow is turned into a Sinner who claims to be in Hell for trying to play God.
- Madame Null is depicted here as a succubus.
- A Hell of a Time: The Utrom Shredder is practically thriving in Hell since he's already a cruel, violent megalomaniac to begin with, and he makes the most of his time there by rebuilding the Foot Clan.
- Alliance of Revenge: The Neo-Foot Clan is headed by the Utrom, Demon, and Cyber Shredders teaming up to get revenge on the Turtles, and a few of their minions have the same goal too.
- Armor-Piercing Question: Satan gives one to Shredder at the end of Chapter 4.Satan: It's ironic that you've yet to capture Lucifer, Shredder. Because in the end, your pride will become your fall. You and I both know that deep down, you're just a scared little man who doesn't want everyone to see him as a weak, pathetic little Sinner who keeps losing to a bunch of teenagers! Isn't that right, Ch'rell? Or do you want me to talk about your dear old dad, too?
- Badass in Distress: Shredder has six of the Seven Deadly Sins in captivity as trophies to prove his superiority to the denizens of Hell and Heaven, and he plans on capturing Lucifer next.
- Big Fish in a Bigger Ocean: Ch'rell is already an incredibly powerful figure in Hell, having built a new army to exact revenge on the Turtles, forcing many power players like the Overlords to serve him, and abducting most of the Seven Deadly Sins. However, according to
Word of God, there is only one being in Hell he seems to fear crossing above all else, and that's Alastor. - Bitch in Sheep's Clothing: Ch'rell lies about being a heroic figure in life who claimed that the Turtles were the real villains. Blitzo buys the act hook line and sinker, but Moxxie has his misgivings about Ch'rell. When Striker arrives after I.M.P leaves for New York, he states how funny he finds it that I.M.P managed to fall for it.
- Black Comedy: As is typical for the Hellaverse, there's plenty of dark humor. One particular example is when the Turtles first discover I.M.P in the first chapter after they murder Hun's group of Purple Dragons. Michelangelo accidentally steps on a heart that he identifies as belonging to Anton since Mikey heard that Anton has valve disease.Michelangelo: Poor guy's never gonna get treatment now.
- Breather Episode: Compared to the violence and action of the first chapter, the second chapter is meant to be set-up for the remainder of the story, showcasing the Turtles and I.M.P getting to know one another, introducing characters like April, Casey, Master Khan, and the Overlords, and showing more of the Shredder gaining power in Hell.
- Canon Character All Along: The first chapter introduces a pair of Purple Dragons named Anton and Owen who are subsequently killed by Blitzo. The second chapter then strongly implies that the two are none other than adaptations of Bebop and Rocksteady.
- Canon Immigrant:
- Kavaxas, a character created for the 2012 animated Turtles series, is featured here as one of the Overlords of Hell and an ally of Shredder.
- Likewise, Jasper Barlow and Madame Null from the IDW comics appear as members of the Neo-Foot Clan.
- Central Theme:
- The parallels between the Turtles' code of honor and I.M.P's more violent methods, and how they come together against a shared enemy despite their differences.
- The complex nature of evil. As the Turtles find out, despite the fact that I.M.P are assassins from Hell hired to kill them, the assassins are just as flawed and broken as any human would be, and Hell itself is more like Earth than they once believed.
- How far someone is willing to go to get what they want. As expected of a diabolical foe like the Shredder, he eagerly manipulates and threatens anyone he sees in his pursuit of power and revenge on the Ninja Turtles.
- Content Warnings: Similar to the content warning at the beginning of most Helluva Boss episodes, this crossover features one that sets the mood nicely.WARNING: THE FOLLOWING CROSSOVER CONTAINS LANGUAGE AND VIOLENCE NOT SUITABLE FOR MINORS. IF YOU ARE UNDER LEGAL DRINKING AGE IN WHEREVER YOU LIVE IN, PLEASE KINDLY GO FUCK YOURSELF BECAUSE THIS STORY CLEARLY ISN'T FOR YOU. IF YOU INSIST ON STICKING AROUND, DON'T SAY I DIDN'T WARN YOU, BUT I WON'T TELL IF YOU WON'T.
- Coincidental Broadcast:
- Twice in the first two chapters. The first one has Loona looking at her phone only to watch a news report about the Purple Dragons, which is what leads them to the Ninja Turtles. The second happens when Donatello says they need to find an Asmodean Crystal, which prompts some breaking news about the Earth Protection Force capturing Barbie Wire and keeping her crystal for research. Millie lampshades the first one.Millie: I'm more concerned about how Loona pulled out her phone at just the right moment.
- Happens again in Chapter 4 when Loona once again checks her phone and tells Blitzo to turn on the news, where Shredder just so happens to be interviewed.
- Twice in the first two chapters. The first one has Loona looking at her phone only to watch a news report about the Purple Dragons, which is what leads them to the Ninja Turtles. The second happens when Donatello says they need to find an Asmodean Crystal, which prompts some breaking news about the Earth Protection Force capturing Barbie Wire and keeping her crystal for research. Millie lampshades the first one.
- Continuation Fic: Shelluva Boss follows up on Turtles Forever with the Utrom Shredder now residing in Hell after his seeming final defeat and plotting revenge.
- Conspicuous Trenchcoat: Blitzo, Moxxie, and Millie don these disguises in New York after Blitzo found them in a store. The disguise falls apart pretty quickly once Blitzo kills a man in public.
- Crossover Foil:
- Each member of the Immediate Murder Professionals is paired up with a specific member of the Teenage Mutant Ninja Turtles in the story:
- As described by
Word of God himself, Leonardo and Blitzo are a Straight Man and Wise Guy duo compared to Neal Page and Del Griffith from Planes, Trains and Automobiles. While both are The Leader of their respective groups, Leonardo is more mature and serious as the oldest brother of the Turtles while Blitzo is a cynical and very crass Bunny-Ears Lawyer who struggles with opening up to others because he believes he's unworthy of being loved. - Donatello and Moxxie are The Smart Guy of both teams. However, Moxxie lacks Donnie's self-confidence and is often the butt of a joke due to being more levelheaded and nonviolent than his teammates, while Donnie is a Technical Pacifist who can sometimes let his empathy get the better of him and isn't as much of a fighter as his brothers unless the situation calls for it.
- Raphael and Loona serve similar roles as The Big Guy with a Hair-Trigger Temper, but Loona's anger issues are because of years of loneliness and irritation with Blitzo doting on her while Raphael's are because of how he carries the burden of keeping his brothers out of trouble. Amusingly, both get quite a lot of Ship Tease together.
- Michelangelo and Millie are the most friendly and approachable of their teams, with Michelangelo being the Plucky Comic Relief of the Turtles and Millie being a Nice Girl and Only Sane Woman compared to the rest of I.M.P. However, both are shown to have more Hidden Depths that they want others to recognize, with Millie wanting to step out of Moxxie's shadow and be more than just his Satellite Love Interest while Mikey states that he is actually much deeper than being the funny wise guy.
- As described by
- To a lesser extent, Agent Bishop gets his own foils in the form of Agents One and Two of D.H.O.R.K.S.
- Loona would also get a brief moment with Karai when the two discuss growing up as orphans before being taken in by their adoptive fathers.
- Chapter 4 has Splinter paired up with Stolas, both of them being single fathers who would do practically anything for their children. However, while Splinter is still relatively well-adjusted, Stolas is plagued by his own insecurities as a parent to Octavia, a lover to Blitzo, and his status as a member of the Ars Goetia in addition to still being targeted by Stella and Andrealphus.
- Each member of the Immediate Murder Professionals is paired up with a specific member of the Teenage Mutant Ninja Turtles in the story:
- Crossover Villain-in-Chief: The Utrom Shredder serves as the primary antagonist of the story and leader of the Neo-Foot Clan, which is a cross between a Legion of Doom and The Legions of Hell made up of antagonists from both series.
- Cuteness Proximity: Millie absolutely adores Michelangelo's cat Klunk upon first meeting him.
- Darker and Edgier: This is far more violent and foul-mouthed than the author's usual stories, a fact that he's proud of for writing his first M-rated story.
- Demographic-Dissonant Crossover: The usually family-friendly Ninja Turtles cross paths with the cast of the adult cartoons set in the Hellaverse. While the Turtles have targeted older audiences and tackled darker subject matter before, with the 2003 animated series being acclaimed for sticking the closest to the original Mirage Comics compared to other versions of the franchise, Helluva Boss on the other hand is a violent and raunchy adult comedy taking place in Hell. The author is aware of how bizarre this idea is, but he also states that he managed to make crossing Gravity Falls over with both FLCL and Soul Eater work when he wrote Fooly Falls and Gravity Soul.
- Disappointed by the Motive: Both the Turtles and even the Shredders aren't amused to find out that Stella simply wants Stolas dead for cheating on her with Blitzo to the point of selling out all of Hell by allying with the Neo-Foot Clan.Raphael: You're literally planning to kill Stolas all because he's seeing another man? I mean, yeah, cheating ain't cool, but if I ever had a wife as horrible as you, I would waste no time in getting a divorce and finding someone else who isn't a bitchy little cock!
- The Dragon: Striker is this to Ch'rell and the Neo-Foot Clan.
- The Dreaded: The Utrom Shredder is this as expected, with the mere thought that he's still out there and plotting his revenge causing the Turtles to panic and Leonardo to pin Blitzo against the wall. But according to
Word of God on his DeviantArt account
, Alastor is the only resident of Hell that Ch'rell is terrified of, as his presence serves as a reminder that Ch'rell will eventually become another one of Alastor's victims. - Due to the Dead: Leonardo creates a makeshift grave for Blitzo's deceased mother in Chapter 4 after the group makes a quick visit to the destroyed All-Imp Circus.
- Early-Bird Cameo: A few Hellaverse characters who had yet to debut by the time the story takes place make appearances here, such as Baxter and the Seven Deadly Sins other than Asmodeus and Beelzebub.
- Even Evil Has Standards: The Shredders' response to learning of Stella's petty grudge against Stolas.Cyber Shredder: So you're willing to sell out all of Hell to us just to have us help you get even with your ex-husband?! If we didn't already have a use for you, I'd slice you open like the pig you are!
- Everyone Has Standards: Despite how crude and foul-mouthed everyone in Hell is, they apparently take issue with the N-word being used.Blitzo: Even we don't take too kindly to that specific word around here! We're not that crass, alright?
- Evil Is Petty: Stella is willing to sell out all of Hell to the Shredder just so he can kill Stolas for her. Both the heroes and the villains are absolutely shocked to discover this.
- Evil Power Vacuum: Ever since Turtles Forever, the Purple Dragons have been attempting to fill the void left by Shredder after his disappearance.
- Foil:
- The Turtles and I.M.P turn out to have more in common than they realize.
- Leonardo and Blitzo are The Leader of their respective groups, only Blitzo has far more issues than Leo.
- Donatello and Moxxie are the brains of the teams, but Moxxie lacks Donatello's self-confidence.
- Raphael and Loona both fill the role of The Big Guy, but Loona has trouble with being treated as a mature adult by Blitzo while Raph carries the burden of keeping his brothers out of danger.
- Michelangelo and Millie are the Fun Personified who both have issues with being seen beyond their basic personality traits, with Millie wanting to be seen as more than Moxxie's Cute and Psycho wife while Mikey claims to be deeper than just being the funny wise guy.
- To a lesser extent, the Earth Protection Force serves as this to D.H.O.R.K.S by being way more competent.
- The Turtles and I.M.P turn out to have more in common than they realize.
- For Science!: Donatello and Moxxie's scene in chapter 2 has Donnie running experiments on Moxxie for the sake of researching Hell, including checking if he really has a Teeny Weenie like Loona keeps mocking Moxxie for. According to a very uncomfortable Donatello, Moxxie's dick is only slightly below the average size of a human penis.
- Fusion Fic: The worlds of both Teenage Mutant Ninja Turtles and the Hellaverse are merged into one like many of the author's other stories. Due to the 2003 series being a children's show that mostly abided by television censorship laws of the 2000s, Heaven and Hell are never really elaborated upon as concepts, allowing the opportunity to confirm that in this universe, Vivziepop's version of Hell is the Hell of this universe.
- The Gadfly: While meditating with Leonardo, Blitzo makes fart noises with his mouth and accuses Leo of farting, much to the turtle's annoyance.
- The Ghost: Stolas is mentioned multiple times in the first three chapters before he makes his first physical appearance in Chapter 4.
- How the Mighty Have Fallen: Subverted with the Shredders. Despite being damned to Hell for their crimes, the three were able to make the most out of it by being their usual monstrous selves and gaining massive amounts of power in the process.
- How We Got Here: The story begins with the Ninja Turtles battling I.M.P in a warehouse on New York Harbor that is decorated with the bloodied remains of numerous Purple Dragon thugs. Up until the climax, the first chapter is devoted to how it got to that point.
- Indy Ploy: After coming to the conclusion that I.M.P likes using this tactic, Leonardo comes up with his own plan on the fly to knock them all out.
- Infodump: Donatello does this in Chapter 2 when he explains his findings about Hell to April and Casey, and gets a little too into his explanation before Blitzo calms him down.
- Internal Reveal: I.M.P learns of the Turtles and Splinter's origins in chapter 2, where the Turtles likewise learn that Shredder wants them assassinated.
- I'm Standing Right Here: Ch'rell invokes this when Moxxie voices his reservations about the Shredder as a client.Ch'rell: You know, Mr. Moxxie, it's rude to talk about someone when they're right in front of you. You should discipline your employees more, Blitzo.Blitzo: Trust me, Saki. The whole universe is out to discipline him for whatever reason every waking moment of his life.
- Knight of Cerebus: As usual, the Utrom Shredder darkens the mood in every scene he's in, particularly in Chapter 2 when he presents the dead bodies of a pair of Overlords he killed before forcing Carmilla Carmine to serve him by threatening her daughters' lives, and later ordering Striker to murder everyone in Rikers Island when he comes to release Master Khan.
- Leave No Witnesses: Ch'rell orders Striker to murder every last prisoner and guard at Rikers Island after stopping by to collect Master Khan and recruit him into the Neo-Foot Clan. Hun is the only other survivor of the massacre due to following Shredder back to Hell.
- Legion of Doom: The Neo-Foot Clan, led by the Utrom, Demon & Cyber Shredders and Kavaxas, consists of many prior antagonists of both I.M.P and the Ninja Turtles. Of note are the generals, consisting of Striker, Fizzarolli, Verosika Mayday, Sir Pentious, Crimson, Master Khan, the Garbageman, Drako, and Savanti Romero. Other members include Vortex, the Foot Mystics, C.H.E.R.U.B, the Necro Monster, and later the Vees, Hun, Stella Goetia, Andrealphus, Baxter, Jasper Barlow, and Madame Null.
- The Legions of Hell: The Utrom Shredder's new Foot Clan consists of many residents of Hell, ranging from hellborn demons to sinners like him, the other Shredders, Kavaxas and the Vees, the Garbageman, Savanti Romero, and Drako.
- Let's You and Him Fight: Ch'rell pits the Immediate Murder Professionals against the Teenage Mutant Ninja Turtles as a way of keeping them both distracted while he uses Stolas's grimoire for his own evil plans.
- Like a Son to Me: Inverted. Michelangelo jokingly calls Millie mom when she tells him not to spill his tea, which causes Millie to burst into Tears of Joy over being called a mother.
- Mama Bear: Carmilla Carmine is forced to submit to Ch'rell when he threatens her daughter Odette's life.
- Manipulative Bastard: Ch'rell manages to successfully convince I.M.P to hunt down the Turtles and hand him the grimoire for protection, using many of the same tactics he used to deceive Leonardo to boot.
- Mass "Oh, Crap!":
- Blitzo and company start running for their lives when Blitzo is caught shooting another man in public.
- After Leonardo knocks Blitzo out with a blow-dart, he throws an explosive shuriken to take down the rest of I.M.P. Millie and Loona frantically order Moxxie, who caught the shuriken, to throw it away before it explodes in their faces.
- The Turtles have this reaction when they learn that I.M.P was hired by Ch'rell.
- The Overlords of Hell have this reaction to Shredder carrying Stolas's grimoire and killing two of their own to intimidate them into joining him, the only exceptions being the Vees and Zestial.
- Mauve Shirt: Subverted with Anton and Owen, a pair of Purple Dragon Mooks who are murdered by Blitzo after the two get a decent amount of screentime, only for the two to appear in Hell as the story's equivalents to Bebop and Rocksteady before getting recruited by the Shredder.
- Noodle Incident:
- Raphael once stubbed his toe and swore so much, it practically became a Running Gag.
- Blitzo mentions that I.M.P got into legal trouble with the Horsemen of the Apocalypse after trying to rebrand the company with their name.
- The events of "Nightmares Recycled" are stated to have still taken place, albeit offscreen. Leonardo says he doesn't remember what happened, to which Raphael says he probably wasn't there at the time.
- I.M.P were once hired as bodyguards for Sir Pentious. We know nothing else other than Blitzo regrets taking the job.
- In Chapter 4, Blitzo mentions an imp named Lincoln who tried to hit on Loona and called her mommy. Verosika also mentions having a similar run-in with Lincoln.
- Apparently, Shredder and Alastor have some history together.
- No-Respect Guy: Due to being Incompetence, Inc., D.H.O.R.K.S is not taken seriously at all by Agent Bishop. However, after their capture of Barbie Wire, Bishop decides to Throw the Dog a Bone for once.
- Nice Job Breaking It, Hero!: The Turtles are not happy to learn that Shredder is still out there, and even more when I.M.P realizes they gave him the grimoire.Leonardo: If Shredder has that grimoire, then he'll no doubt use it to return to New York for revenge. Well, congratulations, Blitzo, your greed has officially put Hell and Earth in danger because of a job. Was it worth it?Blitzo: For the kind of money the squid stain was offering? Yeah, pretty much.Raphael: You are truly Mother Teresa, ain't ya?
- Obviously Evil: Ch'rell, obviously, which makes Moxxie the only member of I.M.P to be suspicious of their new client. Even the mere sight of the Shredder sends shivers down Moxxie's spine upon first meeting him.Moxxie: I'm not the only one who feels just a little suspicious about Mr. Saki here, right? I mean, just look at the guy! His armor's covered in blades, he's got that creepy voice, and he has that weird purple scar on his face! Look at him and tell me he wouldn't seem out of place as a supervillain in a comic book, right?
- Offscreen Moment of Awesome: Alastor once got into a fight with the Shredder in the past and managed to come out of it mostly unscathed.
- Oh, Crap!:
- Hun when I.M.P start murdering his group of Purple Dragons.
- After Blitzo discovers that his team has been compromised and taken to the Turtles' lair, he starts panicking and tries to reach for the grimoire only to realize that he already gave it to Shredder.
- Hun has this reaction when chasing Shredder and Khan into Hell and meeting the Neo-Foot Clan.
- Opening-Up Moment:
- Each member of both I.M.P and the Turtles share some with each other in Chapter 2.
- Blitzo reveals some of his own inner struggles to Leonardo, who offers to let Blitzo meditate with him.
- Moxxie confesses to Donatello about his self-esteem problems brought about by his abusive father.
- Loona and Raphael vent to each other about their anger issues through an impromptu wrestling match.
- Millies voices to Michelangelo her desire to be seen as more than just a Blood Knight and Satellite Love Interest, while Michelangelo says that he has far more Hidden Depths than just being the Plucky Comic Relief.
- Stolas also gets one with Splinter in Chapter 4, confessing to the rat about his struggles to be a caring single father to Octavia and his recent divorce from Stella, to which Splinter responds by giving Stolas his sympathies while disclosing the sacrifices he made for the Turtles.
- Each member of both I.M.P and the Turtles share some with each other in Chapter 2.
- One-Steve Limit: Averted. There are two characters named Baxter, one of them being Baxter Stockman, and the other is Baxter from Hazbin Hotel. Coincidentally, both of them are scientists who either work for Shredder or worked for him in the past.
- Orcus on His Throne: Invoked by Ch'rell as a means to overpower the Turtles once they eventually come after the Neo-Foot Clan in Hell. Aside from returning to Earth to break Khan out of prison, he's making good on that promise.
- Papa Wolf:
- Upon learning that I.M.P was hired to kill the Turtles, Splinter tells Blitzo that he's keeping an eye on him.
- Stolas is willing to sacrifice himself to keep the Neo-Foot Clan at bay so the Turtles and I.M.P can get Octavia to safety.
- Pizza Boy Special Delivery: Parodied when Loona uses her human disguise to pick up the pizzas Donatello ordered, causing the pizza boy to fall head over heels for her. When the pizza boy asks if Loona is doing anything later, Loona instead blows him off.
- Prank Call: When Donatello orders some pizza from Antonio's Pizza-Rama, Blitzo interrupts the call to say that the order should be delivered to someone named Isee Youpee.
- Precision F-Strike:
- Hun, who usually says "Aw crud" in lieu of any actual swearing, does this after accidentally wandering into Hell while chasing Shredder and discovering the Neo-Foot Clan.Hun: Shredder, what the fuck is going on here?!
- Donatello has one of his own when he loses his patience with Barbie Wire in chapter 3.
- Michelangelo says "fuck" during a song about the many words he wants to get away with saying in Hell.
- Even the Shredder of all people gets in on it when he derisively calls Blitzo Stolas's fuck-toy at the end of Chapter 4.
- Hun, who usually says "Aw crud" in lieu of any actual swearing, does this after accidentally wandering into Hell while chasing Shredder and discovering the Neo-Foot Clan.
- Production Throwback: As the Turtles and I.M.P travel the multiverse to Hell, we get a glimpse of Black Rutile traveling nearby while Jasper and White Topaz are in pursuit.
- Psychological Projection: Stella sees herself as the victim of Stolas's Domestic Abuse, when it's really the other way around, proving just how much of an entitled petty bitch she is.
- Psycho Rangers: The Neo-Foot generals are set up as Evil Counterparts to I.M.P and the Turtles.
- Striker to Leonardo.
- Sir Pentious to Donatello.
- Verosika Mayday to Raphael.
- Fizzarolli to Michelangelo.
- Master Khan to Blitzo.
- Savanti Romero to Moxxie.
- The Garbageman to Millie.
- Drako to Loona.
- The Quisling: The Vees eagerly join forces with Shredder after he forces the Overlords to serve him against their will.
- Red Oni, Blue Oni: Fittingly, Blitzo and Leonardo, which is best exemplified during their battle in the first chapter. In contrast to Leonardo and the other Turtles being trained since childhood in the art of ninjitsu, Blitzo and I.M.P are Weak, but Skilled and prefer to wing it in fights.
- Religion of Evil: Kavaxas is said to have been a cult leader in life before becoming an Overlord through building another cult.
- The Rival: Verosika and Velvette are implied to be this given their frosty greeting towards each other when Shredder brings the Vees to the Neo-Foot's headquarters.
- Running Gag:
- A character getting shocked by I.M.P's swearing followed by saying they haven't heard language that foul since Raphael stubbed his toe that one time, usually leading to Raph getting annoyed with it.
- A minor gag in Chapter 4 has an imp named Lincoln being mentioned twice by both Blitzo and Verosika before appearing in person at the end of the chapter and getting tossed in the trash by Loona.
- Save Both Worlds: I.M.P and the Turtles have to team up in order to stop the Neo-Foot Clan from conquering Earth, Hell, and Heaven.
- Ship Tease: Loona and Raphael's rematch ends with the two in a compromising position, which Raph finds hilarious while Loona asks if he wanted to have sex as the two Crush Blush at each other before engaging in some awkward silence. It was intended to be a joke, but after readers compared the two's relationship to Raphael's flings with Ninjara and Alopex, the author made the realization that they actually would make a cute couple.
- Shipper on Deck: Karai of all people notices the tension between Loona and Raphael and tells Loona that she should just admit her feelings for him already.
- Sir Swears-a-Lot: Blitzo, naturally, which Michelangelo lampshades.Michelangelo: We should really put up a Swear Jar at some point. Seriously, is Hell just full of people who love saying bad words all the time?
- Stealth Prequel: The story is revealed to be this to Hazbin Hotel in Chapter 4. When the Turtles and I.M.P reach Pentagram City, Donatello notices the clocktower saying that there are only 360 days left till the next Extermination. The first episode of Hazbin Hotel begins two days later, while the events of the show's pilot episode took place five days earlier.
- Straight Man and Wise Guy: Leonardo and Blitzo respectively, which the author compares to Steve Martin and John Candy as Neal Page and Del Griffith in Planes, Trains and Automobiles.
- Take That!: Apparently both Blitzo and Verosika have had run-ins with an imp named Lincoln who has failed to make advances on Loona and Verosika in the past, likely a nod to the numerous crossovers between The Loud House and the Hellaverse.
- Too Dumb to Live: Blitzo makes many careless decisions that blows I.M.P's cover when they first arrive in New York, like killing a con-man in public and revealing to the Purple Dragons that they come from Hell. He blames this on waking up on the wrong side of the couch when Millie points this out.
- Trapped in Villainy: According to Verosika Mayday, she and most of the Shredders' other minions were forced to serve Ch'rell through being threatened into joining the Neo-Foot Clan, with the exception of Master Khan, the Vees, Kavaxas, and presumably Savanti, Drako, the Garbageman, Striker, and Crimson.
- Uncomfortable Elevator Moment: During I.M.P's elevator ride down the Waldorf Astoria, they have a brief encounter with a lawyer in the building who asks them to kill a barista who got his coffee order wrong that morning.
- Unexplained Recovery: It's currently unknown how the Cyber Shredder is in Hell despite him being a digital engram, thus not an organic being, and how he decided to inhabit Robo-Fizz's body.
- Villain Decay: Despite being as evil and monstrous as ever, Shredder is accused of such by Satan as he has built a powerful army and allied with some of the most powerful beings in Hell or forced them to serve him for no other reason than to get revenge on the Ninja Turtles. This seems to genuinely have an effect on Shredder, as he confesses to Null.Shredder: Madame Null, do you fear me?Null: Of course I do, everyone does! You've only become one of the most powerful Sinners to have ever been taken to Hell! You captured six of the Seven Deadly Sins, have multiple Overlords under your control, and are now in possession of Stolas Goetia's grimoire! How can anyone not be afraid of you?!Shredder: The Turtles aren't. I've been fighting them for as long as I can remember, and no matter how many times I put them on the back foot, they always find a way to humiliate me! [starts gazing at his reflection in a window] Look at me, Null. My best years are behind me. When I was on Earth, I was practically unstoppable! But then I had to find those Turtles, and they started taking everything away from me. My empire, my resources, my minions. I practically had nothing when I was exiled to Mor Gal Tal until that other Shredder found me and I used him to get revenge.Null: And then you tried to destroy the multiverse because you had an apocalyptic panic attack over learning about all the other Shredders beaten by teams of Ninja Turtles. We all heard the backstory. Look, Ch'relly, if you're going to make me into your therapist, save it for after we meet with Vox! Now come on, can't keep such a powerful man waiting!
- Villain Opening Scene: Shredder narrates the cold opening of the second chapter.
- Villain Team-Up:
- It's not just the Utrom Shredder plotting his revenge on the Turtles in Hell, but he has also joined forces with the Demon and Cyber Shredders from the fifth and seventh seasons of the show, along with numerous other characters from both franchises to form a Legion of Doom.
- The second chapter adds Vox, Valentino, and Velvette from Hazbin Hotel to the alliance as three of the only Overlords to willingly side with Shredder, and later Master Khan and Hun.
- Chapter 4 introduces Stella and Andrealphus as members, with Stella and Ch'rell making a deal to have Shredder kill Stolas once he takes over Hell.
- Villainous Fatigue: Ch'rell, of all people, is implied to be suffering from this after being accused of Villain Decay by Satan himself, as he even admits to Madame Null that he's gotten tired of losing to the Turtles so many times.
- Weird Crossover: While the Ninja Turtles have gone into darker territory before, they're mostly known as a family-friendly franchise. Helluva Boss on the other hand is an adult cartoon that wears its target demographic on its sleeve.
- We Wait: Shredder elects to wait until the Turtles realize he's in Hell while building his army. That way, the Turtles will be completely overpowered once they try to stop him. Once the Turtles actually reach Hell, then he finally starts taking action.
