Two Halves
is a Teenage Mutant Ninja Turtles (2012) and Trollhunters crossover story. The premise of the AU is that Karai is a changeling, having replaced Miwa. After the Foot encounters the Kraang, Karai gets the idea that maybe, just maybe, their portal technology could be used to bring her familiar back to Earth from the Darklands, and get her back to her family, who are badass enough to keep her safe.
Tropes found in this fic include:
- Adaptational Species Change: Karai goes from being a human-turned snake mutant into a changeling.
- Alien Blood: As a changeling, Karai's blood is purple.
- An Arm and a Leg: Karai loses one of her lower arms in the process of rescuing Miwa.
- And Then What?: When Karai manages to actually rescue Miwa, she finds that she has no idea what she's going to do next besides continue to protect Miwa, since she didn't really expect that she'd survive.
- Berserk Button: Karai does not like people calling her "Miwa", because she knows that she's just a replacement for the real Miwa.
- Bittersweet Ending: The ending of the first story. On the bitter side, Karai was severely injured rescuing Miwa, she has a long recovery ahead of her, and there are still threats like the Kraang out there. On the sweet side, Miwa has been successfully rescued and reunited with her family, Karai is alive and recovering, and the Turtles and Splinter more or less adopt her into their family as well.
- Body Horror: Karai and Miwa's hearts were swapped in the process of making them linked, and when Karai opens the portal to the Darklands Miwa's heart is drawn to its original host to the point where Karai's chest wound where the transplant took place starts bulging out and leaking blood. Luckily, it calms down once Karai actually finds Miwa.
- Brainy Baby: As a consequence of being in ageless stasis for over a decade and her link to Karai over that time period, Miwa is smarter than you'd expect a baby to be. For instance, she can understand when Karai needs her to be quiet, and later seems to know just how badly Karai is hurt.
- Conditioned to Accept Horror: Due to simultaneously being a changeling operative of the Janus Order and Shredder's adopted daughter in the Foot clan, Karai's been through a lot, and has come to accept a lot of her messed-up circumstances as normal. For instance, after Stockman escapes, Shredder has a minor Villainous Breakdown and slashes her shoulder despite not knowing that Karai helped him. Karai is less upset by the injury itself than the fact that the reason he gave it to her, and not giving her a proper rest period for it, was stupid and illogical.
- Content Warning: Some of the darker chapters have warnings about their contents.
- Death by Adaptation: In canon Xever survives until the end of the series, here Karai kills him while rescuing Donnie.
- Decomposite Character: In this AU "Karai" and "Miwa" are two separate characters, the latter being Splinter and Tang Shen's daughter that Shredder kidnapped, and the former being the changeling who took the girl as a familiar and replaced her.
- Deliberate Injury Gambit: Karai performs one in a fight against Raph in order to give herself an excuse for why her stitches popped.
- Dies Differently In The Adaptation: In this AU, Shredder dies much earlier than in canon, stabbed by Karai in the eye after being poisoned by her, instead of being decapacitated by Leonardo after killing Splinter.
- Explosive Leash: After Stockman escaped despite his mutagen collar, Shredder has Donnie kidnapped to replace him, keeping him in line with a bomb in his shoulder.
- Eye Scream:
- When a feral troll follows Donnie and Karai out of the Darklands, Mikey manages to hit it in the eye with his scythe blade.
- Later, Karai ultimately kills Shredder by stabbing him in the eye.
- Healing Hands: Splinter is able to use his chi technique to help Karai heal by infusing her with life energy.
- How Is That Even Possible?: Stockman is baffled when one of the generators for the portal blows and causes a major power outage, as they're not on the main city grid specifically to keep someone from noticing the fact that the warehouse they're in has a power bill.
- I Control My Minions Through...:
- As in canon, Shredder controls Stockman through Fear, threatening him with the mutagen collar. Karai notes that this is a mistake, as all it means is that, once Stockman has the chance to do so he will betray the Shredder, since he has nothing to lose with his life on the line.
- For Karai, her control over Stockman is one of Mutual Benefit; both of them need the other at the moment, so neither of them can betray the other until AFTER both sides reach their goals.
- Incredibly Obvious Bug: After Donnie shows her what to look for Karai notes that Kraang tracking devices are embarrassingly obvious, and wonders how they've avoided detection for so long.
- Internal Reveal: In Chapter 9, Donatello gets the cliff notes version of the truth about Karai.
- Multi-Armed and Dangerous: Karai's troll form has a secondary set of arms, and she's a skilled ninja so she's definitely dangerous.
- Mythology Gag: Karai's troll form has similar colors to her canonical snake form, and she notes that it has some serpent-like features.
- Rasputinian Death: Thanks to his fish biology, Xever takes more damage that Karai expected before he dies.
- "The Reason You Suck" Speech: Karai gives one to the Shredder right before she kills him, telling him how he failed Miwa (and Tang Shen by extension) by taking her, since she would never have been taken by the Janus Order if he hadn't stolen her himself, and that he was a terrible father.
- Sanity Slippage: Karai’s perspective makes it clear that the Shredder did seem to genuinely care for her once, but the revelation that Splinter was alive and his inability to destroy him and the turtles for good has sent him spiraling. When he kidnaps Donnie to replace Stockman it's unclear if he wants to hurt Splinter by detonating the Explosive Leash in his shoulder or get the science shit Stockman did more, even to Donnie (and even the chapter title is a reference to his dwindling sanity). This is in part because he's caught on to Karai being more amicable towards the turtles. Once Karai bluntly tells him how he failed Miwa, he completely snaps.
- Trauma Button: Miwa has been stuck in the Darklands with only goblin to interact with for a decade and a half, so when she sees the faces of the Turtles she thinks that they're trying to take her away from Karai and starts wailing.
- Triple Shifter: In addition to her normal Foot activities and what the Janus Order has her do, Karai is also gathering Kraang tech and helping set up Stockman's lab to open the portal to save Miwa, and it's noted that her sleep cycle is clearly suffering as a result.
- Villainous Breakdown:
- Shredder flips when Stockman manages to escape, even giving Karai a serious slash across her back in his rage and showing no remorse for his supposed "daughter's" injuries when she (seemingly) pops her stitches from said wounds while fighting Raph.
- After Karai helps Donnie escape from him, Shredder flips once again. Raph even notes that he didn't know that the sounds that the Shredder is making when they try to infiltrate to rescue Donnie were ones that humans could make.
- When he tracks down Karai and she bluntly gives him a "The Reason You Suck" Speech, she can practically see the last thread of sanity in his mind snap.
- Wake Up Fighting: When Karai wakes up in the lair after rescuing Miwa, she quickly tries to bolt before she wakes fully up, and author comments make it clear that if Donnie was closer she would have gone swinging at him.
- Wound That Will Not Heal: Changeling wounds do not really heal on their own. As a result, when Karai is severely injured when saving Miwa, things initially look grim.
