This is something that's been floating in my head for a while now. Enjoy everyone.
Star and Marco stood in front of an interdimensional portal, both looking very depressed, "Well I guess this is it." Star frowned, "I'm going to miss you Marco."
"I'm going to miss you too," Marco frowned and the two hugged, "You'll remember me while you're ruling Mewni, right?"
Star let out a half-hardy, "It's kind of impossible to forget my best bestie."
They pulled away from each other and they heard Star's mother call from the portal, "C'mon Star, we need to return to Mewni."
Star frowned, "Well, goodbye Marco,"
She turned and walked through the portal and Marco watched in sadness as it closed, "Goodbye Star. I love you."
He turned around and slowly walked up the stairs and his parents stared at him and frowned as his disappeared before following him.
They saw Marco walk into the room Star used for the past four years and followed him, "Marco?" Angie said, "Are you okay, honey?"
"Star said that the room will return to normal a few hours after she leaves," Marco frowned, looked around, "I just want to look at the last piece of my best friend as long as I can."
His parents frowned and Rafael sighed, "Hijo, why don't…"
"Hold on dad," Marco said, picking up Star's Dimensional Scissors, "She must've forgotten these! I need to get to Mewni to return them to her!" he opened a portal and jumped through it, "I'll be back before dinner!" his parents looked concerned as the portal closed.
Marco landed inside the Butterfly Castle and was instantly tackled to the ground by six guards. Picking him up and placing a sword against his throat, the lead guard asked, "What business do you have of being here?"
"I'm here to see Star!" Marco snapped, angering the guards, "I have to return something that belongs to her!"
The guards growled and pushed the blade closer to his throat, "How dare you! Don't you know anything about respect? It's Princess Butterfly to you, boy!"
"Star's my best friend, you moron! Take me to her now!" the guards looked annoyed and dragged him away.
They made it to the dungeons and one of the guards threw Marco in a cell, "Get in there!" Marco looked back and saw the guard close the door to the cell, "The Royal family will be here soon enough to decide your fate, kid."
The guard chuckled ad walked away as Marco sat against the wall with his knees to his chest, "What do I do? I could use the scissors to escape but that'll get me in more trouble or I could wait for Star and her family to get here and explain everything and hopefully get out of here alive." He sighed and closed his eyes.
He opened his eyes when he heard the sound of footsteps walking towards the cell and people talking. Soon, the guard that put him in the cell along with Star's parents came into view, "Here's the disrespectful kid, your majesties."
The two looked at him for a moment, "Your majesties, I know you know who I am. I'm friends with your daughter."
The two glared at him for a second longer before King Butterfly said, "Have him executed."
"What?" Marco snapped.
"In the courtyard in one hour," Queen Butterfly ordered. The guard nodded and the three of them left.
Marco sighed and looked out the window, "Well there's no point on running. They'll just find me," he looked at the scissors, "Please be there Star. I still need to give you your scissors back,"
The hour seeped by slowly and soon, a guard walked into the cell and threw a sack over Marco's head and tied up his hands before dragging him away. The guard drug Marco outside where Marco heard cheering, demanding the execution. The sack was removed from his head and he looked around and saw Star standing in between her parents, staring at him in shock.
He was forced to his knees and felt the blade of a razor sharp axe touch the back of his neck, "Marco! Bunny Rocket Blast!" he heard Star cry out.
Before the axe came close to him, he felt Star's arms wrap around him and heard the guard say, "Step aside Princess."
"No," Star ordered, "You lower your weapon and untie him this instant!"
"I have orders from your parents to execute him."
"Then you're going to have to kill me too!"
Marco looked back in shock, "Star? Star what are you doing?"
"Saving you," Star looked back and half smiled, "Don't worry, I'm going to get you out of here one way or another."
The guard looked at the podium and called out, "Your majesties, Princess Butterfly refuses to move unless I let the prisoner go or kill her as well!"
"Star, get away from him," Queen Butterfly ordered.
"No," Star shocked everyone in the crowd, "You sent me to earth, I met Marco, the greatest person in my life and then you forced me to leave him behind! Well if he dies, then so do I!"
A few moments of silence passed and they heard King Butterfly sigh, "Untie the prisoner!"
Marco felt the rope that bound his hands together cut and he stood up with Star still holding him. Marco wrapped his arms around her and heard her asked, "Marco what are you doing on Mewni?"
"I came to give you these back," they separated and he handed her the scissors, I mean they do belong to you." Star sighed and smiled as she took the scissors, "And I…I need to tell you that um…"
Star looked confused and tilted her head to the side, "Tell me what? What's wrong Marco?"
"You know what, screw this." He cupped her cheeks and pressed his lips against hers, shocking Star and everyone around them.
Star closed her eyes and wrapped her arms around Marco's neck, ignoring everyone around them. When they separated, they smiled and heard Queen Butterfly order, "Execute the intruder now!"
Star quickly turned around and pressed her back against Marco as the guard raised his axe, "You're not to touch my husband!" everyone gasped and Marco looked shocked, "Everyone here heard right! Marco's going to be the next King Butterfly and he's going to rule Mewni beside me and if anyone has a problem with it can either say so now or keep it to themselves!"
The courtyard fell silent and King butterfly cleared his throat, "Star, sweetheart, think about what you're doing." Star glared at her parents, "Marco isn't from a royal family. It wouldn't be right if you two married. People will frown at the Butterfly name,"
Star growled, "If you won't let us marry and be the next King and Queen Butterfly, then we're going back to earth and be the next Mr. and Mrs. Diaz,"
"Star, you will do…" before Queen Butterfly could finish, Star opened a portal.
Before Jumping through it, Star looked up and shouted, "You two are invited to the wedding if you want to come, but it's not going to be a royal one!"
The two jumped through the portal and landed in Marco's room before Star closed the portal. Marco looked at her and said, "Star why would…"
Before he could finish, Star pressed her lips against his. Separating, she answered, "Because I love you too, Safe Kid." Marco half smiled and rolled his eyes, "If my parents can't accept that we were going to be the next King and Queen Butterfly then we're going to be Mr. and Mrs. Diaz, rather they like it or not."
"Well I hope this didn't cause an uproar with your parents,"
"I wouldn't care," Star calmly said, "They were going to kill you just because you came to see me. That's a little extreme if you ask me."
Marco chuckled, "Right, well let's go tell my parents you're back." Star nodded and they walked down the stairs, not noticing the portal opening up behind them.
While Star and Marco were talking to Marco's parents, Star's parents walked down the stairs. Star gave the each a hateful glare while Marco gave them a cold glare and Marco's parents looked confused, "Star," her mother started, "Mewni needs a ruler and is you're determined to marry Marco…well we're not going to stop you."
Star stepped back a few steps, "Wait what?"
"You and Marco have our blessings dear. Just come back to Mewni," Queen Butterfly looked at Marco, "I'm sorry we nearly had you killed dear boy. But you did enter the castle without permission and no matter whom you are, that results in an execution."
Marco simply nodded and Star looked at her father, "Dad, is mom being serious right now?"
"She is Star, she is. You know Mewni won't survive without a ruler and you and Marco do seem like you're inseparable."
Star nodded and looked at Marco, "Marco what do you think we should do?"
"It's your choice Star," Marco half smiled, "I'm not going to force you to do one thing when you want to do the other option."
Star half smiled and looked at her parents, "We'll be back on Mewni at the end of the week." Her parents smiled and nodded, "But, I want Mr. and Mrs. Diaz at the wedding too."
"That sounds reasonable," her mother said. The three hugged and King Butterfly opened a portal and the two stepped through it.
Noting much and probably not my best work, but like I said it's been in my head for a while now. Enjoy and let me know what everyone thinks.