Hello again! I have another new AU for you guys today: the Half-Sister AU!
You may have already figured out what's going on here, but I've put a twist on this idea I don't think you're expecting.
Anyways, enjoy!
Marco Diaz was just an ordinary high-school boy. He got straight A's in school, was a green belt in Karate, and had a couple of ordinary friends. The only thing remarkable about him was his well-developed sense of caution, which gave him the title of 'Safe Kid'.
Then his whole life changed one day when his family started hosting a new foreign exchange student.
Star Butterfly wasn't your ordinary teenage girl; she was a magical princess from another dimension, sent to Earth by her parents to master her family's magic wand. She was wild and care-free, laughing in the face of danger with a megawatt grin.
To say their friendship had a rocky start would be an understatement, but the pair quickly became best of friends. Whether it was facing down hordes of monsters after Star's wand or adventuring across the cosmos, they did it together, side by side.
And it was side by side that they currently faced their diminutive menace, a Kappa prince by the name of Ludo Avarius. He had coveted Star's wand for years, and gathered a large army of monsters to help him capture it. Each attempt ended in failure, but Ludo never gave up.
"STAR BUTTERFLY!" he screeched. "HAND OVER THE WAND!"
"Do we really have to do this like right now?" Marco asked. "It's getting pretty late."
Both sides were standing in the Diaz backyard, the sun about to pass under the horizon. No one- not even Ludo- particularly wanted to fight, but Ludo was determined to wear the teens down by attacking them when they least expected. Unfortunately, his plan was working a little too well: after two weeks of constant fighting, he and his monster forces were getting tired too.
"Yeah," Star agreed with a slight yawn. "I know! How about we call it a day, and get back to kicking your butts first thing tomorrow morning? Sound good?"
"SILENCE!" the Kappa shrieked. "We'll be the ones kicking butts this time, and we're going to do it NOW! NOW GET THE WAND!"
Marco sighed; the one time Star took his advice to come up with a non-crazy plan, and it didn't work. He was never going to hear the end of this.
But while he and Star prepared to fight, Ludo's monsters began murmuring nervously amongst themselves. The amphibian monster Buff Frog glanced at the roof, his face ashen.
"WHAT are you WAITING FOR, you IDIOTS?!" Ludo demanded as Buff Frog began to whisper in his ear. "I said, 'GET THE- huh?"
The Frog Man whispered again. Ludo gazed slightly upward, and his green face turned several shades lighter.
"You know what? It's been a long day," Ludo chuckled nervously, "I think we could all use a break from this little game of ours, don't you?"
Star and Marco exchanged a confused look.
"Exactly! You're tired, I'm exhausted, why don't we all just go home and get some rest?" Whipping out his scissors, the 'exhausted' Ludo cut a portal faster than they'd ever seen before. "C'mon boys, let's hit the hay. Quickly now!"
The pair was still standing there staring as the swirling vortex closed.
"Well, that was new," Marco commented.
"Yeah..." Star murmured, an uncharacteristically thoughtful expression on her face. "Weird..."
"So, ready to catch some z's?"
"Actually, I'm getting kinda hungry."
"Want me to make you some nachos?"
"Yes, please!"
And with that, Star and Marco headed inside, neither one of them noticing a pair of eyes watching from the roof, shining like emeralds in the setting sun.
By the time the nachos were done cooking, the teens weren't quite as tired, so Star decided a late-night movie marathon was in order.
"Why not?" she argued. "We've already got nachos to snack on."
Marco didn't find any obvious flaws in her logic, so he agreed. Together, they got everything set up: TV was on and ready to start the movie; nachos were ready as previously mentioned; the couch was prepared with their gigantic fluffy blanket ready to be flung over-
Wait, where was the gigantic fluffy blanket?
"Oh, dip!" Star groaned when he asked. "I left it upstairs!"
"Well, I'm already up, so I'll go get it." Marco offered. "Is it in your room?"
"Yeah. Thanks, Marco."
"No problem."
Marco made his way up the stairs and to his housemate's room: a massive, three-story tower springing out of the guest bedroom. He carefully stepped into the dark room, trying to avoid the piles of assorted clothing, weapons, and jewelry strewn over the floor.
It didn't take him long to find the blanket; Star had set it by the door, clearly intended to be brought down with her. Marco reached out...
...and paused. Something was off, and not in the 'typical-Star' kind of way.
A flicker of movement caught his eye, and he froze. It could easily have been his imagination, or one of Star's many magical constructs... but Marco would rather not take chances. He redirected his hand toward the light switch-
Something struck him hard, and Marco landed on his back, winded. Okay, who- or whatever this was, they weren't friendly.
"I would keep quiet if I were you." The soft feminine voice spoke with a slight British inflection, as though they hadn't quite picked up the full accent. For some reason, it was also vaguely familiar. "Go back downstairs and forget you saw anything."
"And leave you here in my best friend's bedroom?" Marco countered, rising to his feet. "Yeah, hard pass."
"Oh? And what's the problem with that?" The intruder moved closer to the open door, allowing him to catch a glimpse of their silhouette before they seemed to vanish. "There isn't much a girl would want from another girl's room." Actually, she looked a lot like Star.
"That is so not the point!" Marco replied sharply, before catching an equally sharp blow to his ribs. The intruder might look like a human girl, but the reptilian scales covering her exposed forearm were enough to prove otherwise.
"So, you can fight back," the lizard girl's green eyes caught the light from the door behind Marco, pupils narrowed into slits like a cat. "Excellent."
Star sat on the couch, watching the bowl of nachos cool. She had been waiting for her bestie to return with their blanket, but he hadn't come back yet.
It really wasn't like her to worry, but it wasn't like Marco to take this long for a simple blanket-finding mission either. Something wasn't right, and it wasn't just the weird thumping noises coming from upstairs. Although that did seem like something she should worry about.
"Okay, Marco," Star stood, brandishing her wand. "I'm coming."
A pause. "And if you're not in trouble, then I'm probably gonna look real dumb."
After a minute of trading blows with the intruder, Marco had gained a rough understanding of his opponent. Like Star, she was strong and quick, and knew how to put both traits to good use. Her fighting style wasn't one he recognized, but it was close enough to Star's that he could anticipate some of her moves.
Unlike Star, she had a tail. A long, flexible tendril that the lizard girl could use as another limb, and did so freely.
It was unlike anything Marco had faced before, yet he was pleasantly surprised to find himself holding his ground.
And apparently, he wasn't the only one.
"Impressive," she said, smirking excitedly. "Most of my fights are over by now."
"Why's that? Quick to lose?" Marco's quip nearly earned him a broken nose as he narrowly dodged the intruder's foot.
"On the contrary," the girl lunged with a flurry of attacks that Marco could barely keep track of. "I'm quick to win."
Not wanting to be pushed back on the defensive, Marco lashed out- and when he felt the brush of scales coiling around his wrist, he knew he had messed up.
A sharp tug sent him sprawling on the ground again, where this time he was quickly pinned.
"Told ya," the lizard's tone told Marco that she wore a smug grin behind his back. "Do you yield?"
"Marco?"
Before he could respond, Marco caught a glimpse of someone standing in the doorway as the light clicked on. Brown eyes met brilliant blue, and Star gasped at her bestie's predicament.
"MARCO! Blinding Rainbow Blast!"
With a flash of light and the familiar chime of Star's magic, the weight of the intruder flew off his back. Marco worked to get up as Star rushed to his side.
"Ohmygosh, Marco, are you okay?!"
He took a moment to assess his condition. "Yeah, I'll be okay. That lizard girl gave me some nasty bruises, but nothing's broken."
Star gave him a confused frown. "Lizard girl?"
"That would be me."
The pair turned to see the intruder in question rise from the middle of the room, wobbling slightly. Standing in one place with the light on, Marco could clearly see who he had been fighting- and how closely she resembled his best friend.
The lizard girl's frame was nearly identical to Star's, including a mane of silver-blue hair that reached her knees. She wore a sleeveless black dress that complimented her grey scaly skin as well as helped her blend into dark rooms.
She even had marks on her face like Star- only they were crimson stars instead of pink hearts.
"Hello, Star." The girl tried to give them a friendly wave, but discovered her right arm was no longer attached to her shoulder. Gritting her teeth, the arm regrew. "Urgh, how does Father do that all the time?"
Star gaped at the intruder, her eyes bulging. "Dawn?" she whispered.
The lizard girl smiled. "It's been a while, hasn't it?"
Marco blinked. Did they know each other?
They did. And judging from the way Star sprinted to hug the lizard girl, they knew each other very well.
"H-how did you find me?" Star asked, her voice quavering.
"Simple, really," Dawn answered with a grin. "Father keeps tabs on everyone. All I had to do was ask him. The hard part was actually getting here."
Star giggled. "So how'd you do that?"
"I had to get my scissors from the Vault."
"And you couldn't just ask Father to open it?"
"Well," Dawn's grin turned mischievous. "I didn't tell him they were in there."
"Dawn!" Star scolded playfully. "I still can't believe you really came."
"Of course I did! You promised me a sleepover."
"That's right, I did!" As though she just remembered his existence, Star turned back to Marco. "Is it okay if Dawn stays the night?"
Marco debated it in his head. Star seemed to trust Dawn, and he trusted Star's judgment for the most part.
But he still remembered how Ponyhead had treated him when she came to visit. Not to mention the lizard girl had nearly pummeled him less than five minutes ago.
On the other hand, the lizard girl had nearly pummeled him less than five minutes ago. Probably wouldn't be a good idea to risk antagonizing her.
"I don't mind, Star. But if you're going to have girls stay over in the future, I'd kinda like to be introduced to them first."
He meant the last part as a joke, but Dawn reacted immediately. "Oh! Of course, where are my manners?" The lizard girl shook her head in embarrassment, then did a small curtsy. "Dawn Truffle Butterfly, second in line to the throne of Mewni."
"My sister!" Star added.
At that moment, Marco firmly believed that he had heard just about everything.
About thirty years ago, when Queen Moon Butterfly the Undaunted was a young teen, a monster saved her life.
Not long after Moon had turned fourteen and received the royal wand, her mother had taken the young princess on a tour of the Kingdom. She would make many lifelong friends on that trip, including the timid Prince River Johansen.
But shortly after departing from the Jaggy Mountains, their company was ambushed by a band of rogue monsters. Lacking experience with her wand and separated from her mother, the young princess Moon was no match for the savage brutes. Fearing for her life, she gave a call for help.
Her call was answered, not by any in her group, but by a masked monster who called himself Toffee. Dispatching the rogues with ease, Toffee reunited Moon with her mother, asking for nothing in return. It wasn't until their return to the castle that Moon learned her savior was the sole heir to the monster kingdom of Septarsis.
Over the next three years, Moon would grow closer to both Toffee and River, forging strong bonds with them as individuals and a group. They would aid the princess in her darkest hours, including her premature ascent to the throne.
And when the time came, the young queen could not bear to choose one over the other.
And that's how you take the 'Star's sister' cliché and make it original! Please let me know what you think of this AU, I haven't got a lot of feedback here and would really appreciate it.
This was my entry for the January 2022 Writing Contest. I didn't place, but I still had fun!
I have to say, I was very happy to finally get this story finished! I started working on it back in August, but could never get it to work. Original characters are hard to pin down sometimes.
Anyway, see you when I see you!