Ok folks, let's start this!

So, for reference. The characters in this are all based on older fics - Hiccup is based on Serialcup from Making A Killing (Valka is also based on that fic's version). Haden is based on Rebelcup (from Expectations) but is also an OC I've written in a couple of other fics. Astrid and Lillian are identical twins (best known from Confusion). Hiccup and Haden are also identical twins. And, as you might have guessed, there will be, amongst other things, murder and incest. Not at the same time.

It's not necessary to have read any of those fics, mostly that's just so anybody new here is aware these are all established characters/personalities for me. If you want to go read them (and leave nice comments), you're welcome to.

If POV gets confusing (because I'm likely to write from all four main characters POVs at some point) let me know and I'll specify who's POV it is in future.

That's all I can think of for now... let's go!

-HTTYD-

Hiccup stomped through the door after one final look behind him. As he locked the door and pushed the deadbolt in to place, he heard the familiar three-tap of his mother, her walk aided by a walking stick. He lifted his helmet up and took off his boots, then picked them up to carry with him.

Bloody footprints were a pain to get out of the carpet.

Valka found him in the kitchen, stripping off his bloodied clothes. The sight of his bare skin, covered in old scars and somebody else's blood, was normal only to her. Only his mother knew the tales his body told, as it was her story too. Under her baggy jumpers and loose bottoms, Hiccup knew he'd find similar scars.

"Did I wake you?"

"No no. I was waiting up for you."

Hiccup nodded.

"Go sit down. I'll join you when I've cleaned up."

He left his clothes and weapons to soak, then headed to scrub off evidence in the shower. Hiccup put his more comfortable prosthetic back on his leg, then pulled on a well-worn hoody and pyjama bottoms before he padded out to the living room.

"Tea?"

Valka nodded, so Hiccup went to put the kettle on. Once they both had steaming mugs in front of them, Hiccup settled in to the recliner chair, leg rest up to let him relax more.

"Were you careful?"

"I always am."

And she always asked. Hiccup was happy to reassure her; getting arrested for murder would have meant his mother was left alone with nobody to care for her. That was not going to happen, not on his watch. So Hiccup was always as careful as could be.

They hadn't caught him yet.

"How are you feeling? Do you need anything?"

Valka shook her head.

"I just wanted to be sure you got home safely."

They drank their tea in comfortable silence, and Hiccup settled his mother in bed for what remained of the night. He finished his clean up, then took himself to bed for a couple of hours rest. He was sore after his night's... work, so he took a painkiller before he laid down to sleep. Even so, he woke up after only a short slumber, a little groggy as he limped to the bathroom.

When he was done emptying his bladder and brushing his teeth, Hiccup checked his phone. There was a text from Astrid, complaining about getting up early to go running. Hiccup chuckle to himself as he tapped out a reply.

"The only person who makes you do that is you."

It was... strange, the thing with Astrid. Hiccup had never really thought about dating before he met her. But the personal trainer with a side hobby in writing murder mystery fiction had somehow found her way in to his life, though things were still pretty fresh and new. They hadn't done more than kiss. He hadn't met her sister yet. Astrid hadn't met his mother.

And she didn't know Hiccup was the Night Fury.

That was the name he'd been given by the media, as he only killed at night, and was known for being particularly vicious in his kills. Hiccup supposed he couldn't argue, easily able to remember the way rage burned in his blood each time he took a life.

Hiccup flipped the news on the TV and settled in with his phone and a fresh mug of tea, waiting for Astrid to answer his text after she'd finished her run.

"That's not the point. Are you busy tomorrow afternoon?"

Hicccup hummed as he mentally checked his schedule, then shook his head to himself.

"No more than usual. Why?"

"I know you can't be gone too long. But I was hoping you'd meet my sister."

He blinked, briefly surprised.

"Is there something happening tomorrow in particular?"

"No. Just that she's got plans today, but is very keen to meet you."

Hiccup swallowed nervously. Was he ready for that? He always felt like his and Astrid's relationship was never going to go anywhere in the long term, as he had a pretty big secret that would no doubt be tough to hide from her forever. It made him feel awkward and guilty around her at times, but it was difficult for him to deny the pull to her.

Meeting her sister - who he knew Astrid was very close to - felt like a step towards commitment.

"Alright. What time do I need to be free?"

His latest kill was making the rounds on the news by the time Valka woke up, and Hiccup fixed her breakfast and got her morning medications sorted with the report playing in the background. It was a pretty normal morning for them. As his mother knew him better than anyone, she could always tell when Hiccup had something on his mind. She recognised the way he grew twitchy in the build up to a late night walk, knew when Hiccup was having more trouble than usual with pain or sleeping.

"What's wrong son?"

"Oh. Astrid asked me to meet her sister."

Haden whistled to himself as he put the finishing touches on a paint job, then stepped back to admire his handiwork. He was very proud of his work, and so he smiled and left the paint to dry. With no other work immediately necessary, he stripped off his overalls and headed to the building next door.

"Yanno, if you keep walking in here topless, I'm going to get ideas."

Eret joked as Haden walked in. He tended to only wear shorts or comfy jeans under his overalls, because it got hot in them!

"You can have all the ideas you like, so long as you keep them to yourself."

Haden joked back, and Eret gave him a wink before he turned back to the car he was working on.

"You done for the day?"

"Only had one bike in, paint work is done so yeah. I thought I'd come have a late lunch in here, check on my work, lock up and then I'm gonna go clean up before Lillian comes over."

Eret laughed.

"Oh, she's coming over again? I should go spend my night at Dagur's if I wanna be able to sleep."

Haden snorted, shaking his head. He and Lillian hadn't known each other that long, but the last time she visited, things had been quite... noisy, judging by Eret banging on the door to yell at them. Which was rich, given how loud Eret's boyfriend was.

"She's not spending the night. Just coming over for dinner."

"And to get wrecked by the pierced pole in your pants."

Haden put a hand over his face and groaned. He and Eret lived together, and after spending so long getting various tattoos and piercings to decorate his body, Haden felt pretty confident in said body. And Eret was shameless, so the two had seen each other naked many times. Plus Eret had been absolutely fascinated by the knowledge Haden had gotten his cock pierced.

Which of course meant his dear best friend made terribly inappropriate jokes.

Haden knew it was all in jest, though. Eret had pretty much saved his life, and while he had the vocabulary of a drunk sailor and flirted shamelessly with just about everybody, he never overstepped a boundary and had been an incredible friend to Haden ever since they first met. He'd helped Haden learn more about mechanics, given him somewhere to live when he ran away from his overbearing, traditional father after home became unbearable, and then gifted Haden the space to set up his own shop specialising in motorcycle work.

Hel, Eret's Saami family were more of a family to Haden than his own father was by then. He didn't know his mother - his parents had divorced when he was a baby, and so all Haden had was an old photo of the two at their handfasting that his aunt had stashed in a photo album. Nobody knew where to find her, and Haden wasn't nearly as gifted with computers as he was with things that had wheels. Plus, it seemed she had never tried to find him.

Haden shook off those thoughts, and focused on throwing trail mix at Eret until the man joined him at the side to eat lunch. He relaxed in the company of his friend and the two chatted over sandwiches.

"You wanna join us for dinner?"

Eret considered the offer, then shook his head.

"Appreciate it, but nah. I'm gonna go see Dagur anyway. He's had a tough week, I think I'll have a better chance helping him unwind if it's just the two of us."

Haden laughed at the terribly unsuble look on Eret's face.

"Don't break him."

Eret winked.

"No promises."

Once they were done, Haden wished his friend a pleasant afternoon and went back to his own workshop. He did a little admin work, locked up the shop and walked the fairly short distance to the house he shared with Eret.

A quick check in the kitchen confirmed he had everything in for the dinner he had planned, so Haden headed to take a long, hot shower. Eret sometimes teased Haden about how long it took him to finish up in the bathroom, but in Haden's defence there was a lot to do. He had to make sure all his piercings - one in his lip, one in his tongue, one in each nipple, five curling up over one ear and scale-patterned tunnels in both stretched ears, and of course the one in his penis - were clean and their jewelry was tight. He had to check the root regrowth on his dyed hair. And then he had to moisturise each of his tattoos, which covered most of his body by then. And since Eret had tattoos too, they kept the moisturiser in the bathroom.

So really, it was Eret's fault.

At least his choice to keep his hair short (it had been longer and shaggier for a while, but Haden found it too much to dye when he changed the colour) meant it was quick to blow dry. Once he was done, he wriggled in to his favourite worn-in skinny jeans and brightly coloured socks, then ruffled his hair messily and smudged some black around his eyes.

Eret stopped by long enough to shower and change, then wolf-whistled at Haden in his jeans and apron and said he'd see him the next morning.

"Want me to bring breakfast to the shop?"

Haden offered. Eret nodded eagerly - he was more than competent in the kitchen, but also liked to make Haden cook for him. Luckily, Haden loved to cook.

"I will love you forever if you do."

Haden laughed, promised and wished his friend a pleasant evening. Alone again, he went back to making dinner for two. It was cooking away in the oven when he heard a knock at the door, and skipped over to answer it with a smile. Lillian was on the other side, and the two exchanged a smile as Haden invited her in.

"That is a look."

Lillian said as she gestured to Haden's attire.

"You complain if I wear a shirt, and complain if I don't. I can't win!"

He joked back as he led her toward the kitchen.

"I meant the apron."

"This one is Eret's. I happen to think I look great in this bikini."

He gestured to the print on the apron - a toned, tanned lady in a polka dot bikini. Haden did have one of his own with dragon scale patterns on it (obviously), but it was in the wash after a messy baking session the day before. So he had Eret's joke choice instead.

"I mean, yeah. But the apron doesn't have your tattoos on."

Haden chuckled and nodded his agreement.

"That is the downside. Dinner is in the oven, so make yourself at home. Want something to drink?"

Lillian nodded, putting her messenger bag down to take off her hoody. The soft grey t-shirt she had on underneath was a little too big for her, but the comfy look suited her and Haden thought she looked adorable. Plus, he found the fact Lillian felt comfortable enough to not 'dress up' to impress him even more attractive. He was more than 'extra' enough for two people, and wanted anyone he dated to feel like they could just be themself with him.

Dinner was simple, just seasoned chicken and vegetables baked nicely in the oven, with a fresh salad on the side and some of the cake he made yesterday for dessert. But it was satisfying, and the conversation flowed easily enough between the two as they ate. The conversation continued as they went to sit outside to relax and digest a little. Lillian vented about university stress and parent problems. Haden could relate, given his own less-than-perfect parent situations.

"Oh, I just remembered something. Wait right here."

Haden waited, bemused, as Lillian ran back in to the house (hopefully not to just leave), then returned with a book in her hand. She held it out, and Haden accepted the unexpected gift.

"Uh, thanks?"

"You said you were interested in reading my sister's books. So she said you could borrow a copy of her first one."

Haden scanned the cover, and saw Astrid Hofferson printed along the bottom. Same surname as Lillian, he realised.

"Oh! Yeah. Thank you! I'll make sure it doesn't disappear. And if I like it, I promise to buy my own copies of this and the rest."

Lillian beamed. Her smile was beautiful, Haden thought to himself. When they headed inside, he put the book up on a shelf out of range of greasy mechanic hands so it didn't get accidentally filthy when he or Eret came in from work.

When she asked where his bedroom was, Haden felt his belly flutter in anticipation at the heat in her eyes. It wasn't her first time in his bedroom, but he understood the implications of the request as she grabbed his hand and led him that way. Though she came across as quiet and reserved until she relaxed, Haden was pleasantly surprised to find quite the opposite when they were in bed together.

Her fingers traced the shapes inked on his skin, teeth playfully nipping at his collarbone as she worked to unbutton his jeans. Their foreplay was more like playfighting, wrestling for top until they could pin the other down to get hands on each other properly. Lillian complained his jeans were 'too damn tight', so he had to roll away to peel them off himself.

"If I'm not on the bike, I choose skinny jeans because they don't fall down. It's hard to find clothes that fit when you're over six foot of string bean."

Haden had to assume he inherited his mother's build, because he definitely hadn't inherited his skinny shape from his father. That thought quickly left his mind when Lillian peeled off his boxers, careful not to catch on anything as she got him naked. She found the piercing rather intriguing, though Haden knew she was a little nervous to interact too closely with it. He wasn't going to push it, because having it get caught on teeth was not fun for anybody.

Playful and enthusiastic as a lover, Lillian was just as active when they got more in to it, though they did have to slow down so Haden could carefully apply the condom over his piercing. He'd warned Lillian there was a slightly increased risk of breakage in advance, but that he was regularly tested and clear, plus he was happy to go get her a morning-after pill if she needed it. Or take it out, which Lillian declined as she was curious how it was going to feel. So far, things had been fine on that front.

Haden had no complaints about her pushing him down on his back and straddling his hips, both taking their time with the initial penetration until Lillian found a comfortable position. Once she was settled, Lillian rode him eagerly, splaying her hands across his tattooed chest for support. Haden was happy to be along for the ride, resting his hands on her powerful thighs as he enjoyed the view of her naked on top of him.

Lillian was also adorably snuggly in their post-coital rest, and Haden could not deny he was absolutely smitten with the blonde.

"Do you have to go? You're so cuddly!"

Haden complained, which made her laugh and nuzzle against his chest.

"Yes, I have an early class tomorrow and I just don't think I'd get enough sleep here."

He gave a joking pout, but acknowledged her reasoning. Plus, if she wasn't comfortable spending the night, he wasn't going to press the issue.

"Need a ride home?"

Her eyes lit up.

"On the bike?"

Haden nodded with a grin.

"Only way to fly!"

"Absolutely."

Lillian agreed. They cleaned up and lazed around together a little while longer, then Haden packed up some leftovers for her to take home with her, since neither Eret or Dagur were there to help him get through them. Lillian followed him through to the garage, waiting patiently for him to lock up the house before he wheeled his bike out of the garage and went back in for Lillian.

"Safety first. Jacket and helmet."

After stealing another kiss from the smiling blonde, Haden gave her his spare riding jacket and a helmet, helping her put it on properly over her braided hair. She lifted the visor to admire Haden as he put on his riding leathers and boots. His motorbike was his absolute pride and joy, built completely from scratch by him. It was modelled to look like the same dragon he had tattooed over his back, with the wings around his sides and the tail curling up around his neck. The 'tail' part of the bike formed a nice, solid back seat for a passenger.

"Hold on tight."

Haden said, waiting to feel her arms wrap tight around his middle. The dragon roared to life beneath them, and they sped off in to the night. Lillian held fast the entire trip, until they pulled up on to her street. Haden had never been to her home, but he'd ridden his beloved bike all over town and so he had no trouble finding the right area. He slowed to a stop halfway along, and Lillian clambered off with a slightly awkward gait. Straddling a bike took some getting used to.

He removed her jacket and helmet, flipping open the storage compartment on his bike to stash them for the ride home. Lillian gestured for him to remove his own helmet, and leant in to kiss him goodbye.

"Thanks for the ride. And the ride home."

She winked and giggled, then turned and headed toward the house next door to the one he'd stopped in front of. He waited to see her in, then heard somebody shout from the top window of her home.

"Nice bike!"

It almost sounded exactly like Lillian. Haden looked up, and had to blink a couple of times. Wow. They really were identical twins. Haden waved.

"Thanks!"

Her expression was a little... strange, but Haden wondered if she just thought his voice didn't match the biker look. He'd been told that before. Shrugging to himself, Haden put his helmet back on once he heard Lillian's front door close behind her, then revved up and headed back home.

The next day was pretty uneventful - he made breakfast for himself and Eret, amused by the colourful new lovebites on his friends neck and shoulders.

"You guys should stop for snack breaks, looks like Dagur gets peckish."

He joked. Once they had eaten, Haden headed next door to get to work himself, in a bouyant mood after his very pleasant dinner date with Lillian. Their relationship was still very much 'casual', as Lillian had been up front that she didn't have time for something serious with her final year of university going on. Haden didn't mind; they had fun together. And if he was very lucky, she'd have more time when university was over and they could see about something less casual. But Haden wasn't going to focus too hard on that, as he preferred to live in the moment and enjoy what he had in the now.

As he was preparing to close up for the day, Haden's personal phone vibrated on the side. Wiping his hands on a rough cloth, he picked it up and saw Lillian was calling him. A little confused, he answered.

"Hello?"

"Hey. Could you come over? Like... right now?"

He frowned. Lillian sounded a little out of sorts.

"Is something wrong?"

"Not... wrong. Just... it's hard to explain. I promise there's no serial killer in my house."

He was still pretty confused, but Lillian was insistent.

"Alright. I need to clean up from work, then I'll head right over."

Haden quickly filled Eret in on what little detail he had, and promised to explain when he got back. He had a quick wipe down with mechanics soap to get the grease off his hands and face, then jumped in to his leathers and on to his bike. Retracing the journey he had only made the day before, Haden pulled up to Lillian's house. He hadn't even taken off his helmet when the front door opened, and he saw... well, he thought it was Lillian, but it might have been her sister, waving frantically for him to come inside. Once he'd activated the alarm on his bike, Haden took his helmet off and headed to the house with it tucked under his arm.

He didn't even get a chance to offer to take his boots off before he was pulled through to the living room. Haden stopped dead when he got there.

Though the man had no tattoos or piercings visible, and was swamped in a hoody that looked two sizes too big for his narrow frame, and his hair was l1onger and shaggier... it was still somehow like looking in a mirror. Identical blonde twins stood looking back and forth between the two as Haden tried to process what was happening. Before he managed to find his voice, the unexpected mirror image spoke first.

"Haden?"

-HTTYD-

DUN DUN DUNNNNNNN.

Additional note for FFN readers: this is marked as complete because for now, only this first chapter is going to be done. I don't know when I'll get to the rest. But this has been idling for about a year as an idea, and I needed a creativity booster.