What if, in Running with Scissors time didn't work differently in Hekapoo's dimension? What if Marco really was gone for sixteen years? What would have happened to Star and the others in that time?
AKA, Fanfic excuse for me to imagine adult!Star as an expy of Furiosa from Mad Max.
"Not bad for a human. You truly earned these."
Marco gazed at the freshly forged dimensional scissors, his name engraved on them in a language he now was more familiar with than any from Earth.
"I underestimated you," Hekapoo smiled. She had grown fond of Marco after all these years. They had become the best of friend-enemies.
Before either of them could any more, the door to her forge-lair slammed open.
"HEKAPOO!" Dust poured in from the outside wastelands, leaving the intruder in silhouette. Marco reflexively drew his sword while Nachos the dragoncycle growled. Hekapoo turned to face the intruder but with a look of curiosity and amusement more so than worry.
"WHERE'S MARCO?!" The figure emerged from the cloud of dust. She was a woman with buzz cut hair, an eye patch, and a crude prosthetic right arm which had a grip holding a familiar wand in place of a hand or claw. Emerging from her back were purple, crown shaped wings, each covered in scars and stitched up tears. She wore the remnants of a tattered green dress with a purple octopus on the front as a tank top.
There was something intimately familiar to Marco about several of those details, but it was one thing particular that caused him to drop his sword in shock. The pink hearts on the woman's cheeks.
The two long-lost friends ran to each other for a quick reunion hug. "We have so much catching up to do! Look, I got my scissors!" Marco held his dimensional scissors for Star to admire. She slapped them away.
"You've been gone all this time for some stupid scissors?" Star's heart marks changed to skulls, which fit her current appearance far better, Marco noted.
"I lost yours, I had to get them back! Well technically these are a replacement," Marco explained, nervously scratching the fire induced bald spot on the back of his head.
Star stared at him. "Do you even realize how long you've been gone?"
"I… I hadn't really thought about it. With all the danger and life-threatening adventures everything just… blended together. A few months? A year? Two years?"
"Sixteen, Marco. You've been gone for sixteen years."
Marco looked again at Star, while his attention had been taken by the buzzed hair, prosthetic arm and apocalypse-ready wardrobe, he had failed to notice how much taller, muscular and… full figured she had become. He then stared down at his own heavily muscled body.
"Aww man, I thought puberty had just been really kind to me."
Star frowned and shook her head. This gave her a moment to look at Marco and how he changed, going from the scrawny safe kid she could barely remember into this… road warrior. Her gaze drifted to Marco's exposed stomach, much as Marco's gaze look to her's.
"Abbbbbssssssss," the both muttered in awe at each other's physiques.
Hekapoo snapped her fingers, breaking Star and Marco out of their ab-induced dazes. "Yeah, sorry about that, Princess. Marco was on a trial and no one is allowed to interrupt a trial once its begun. That's why you found him as soon as he got the scissors."
Star just glared daggers at Hekapoo, her anger from before reignited. She shifted her attention back to Marco. "Your parents, your friends, and me, we were all so worried about you, Marco! I spent years searching across every dimension I could find. Your parents gave up hope, but I kept looking and looking until I had to become queen of Mewni. Even then I kept sending guards out to search for you and look for you myself whenever I got a chance to leave court."
"I had no idea-" Star cut Marco off before he could finish.
"Eventually my mom convinced me to agree to a political marriage, but the groom turned out to be a minion of Ludo's and he tried to kill me as soon as the ceremony was over. Ludo took over Mewni and I barely escaped with my life! I did get a sweet robot arm out of it, though."
"Is that also how you lost your eye?" Marco asked.
"What? This thing," Star poked her eye-patch. "No, it's a fake," she flipped the eye-patch to show her perfectly functional left eye. "I just thought it looked cool."
"Buff Frog's family found me and nursed me back to health, and with nothing else left, I went back to searching for you full time,"
"Star, I'm so sorry, I had no idea," Marco stared at his feet. "Well, you found me. Now what?"
"Until now it was just me against Ludo's tyranny. Even I didn't like those odds." Star put her hand on Marco's shoulder. "But you and me, like old times, I like those odds a lot more."
"So what do you say Marco, wanna' overthrow a dictatorship and take back Mewni?"
Marco grinned. "I'll get Nachos."