I said I was going to take this challenge and here you go. Enjoy the first chapter.

Star Butterfly, monster princess of Mewni, panted as she ran through the Forest of Certain Death. Hearing the shouting of the guards chasing her echo throughout the woods, she looked back before tripping over an exposed root. Groaning, she looked back and her eyes widened when she spotted the guards, along with her mother, Moon and her husband River, standing over her, glaring at her with narrowed eyes, "Star," her mother said in a stern voice, "I knew the day I was sexually assaulted by that monster that I should've terminated the pregnancy, but here we are, and now we will-" before she could finish, she, River and the guards were knocked back with a force.

They looked up and saw a pair of glowing red eyes glaring at them before a loud hiss filled the air. Screeches soon followed and they looked up to see a flock of bats flying towards them. Star looked up and saw a teen with red eyes and pale skin standing above her, "Are you okay?"

"You're not going to kill me!" Star hissed before scratching the teen's cheek, "So what if I'm part monster, it doesn't-"

"I'm not going to kill you…I don't kill my own kind," Star looked up in confusion and saw a pair of pure white fang reflecting from the moonlight, "We have to go. My Familiars won't be able to hold them forever," Star looked back before the teen helped her up and the two began running in the opposite direction.

Star fell forward and hissed in pain and quickly grabbed her ankle, "Damn it…I think I sprained my ankle," the teen looked back up to see the flock of bats before looking down at the monster princess and picked her up bridal style, "And what are you doing? You're going to get us both killed,"

"And I'm a Vampire, so I'm pretty sure I can outrun those jokers. Just hold on tight," Star narrowed her eyes before she wrapped her arms around his neck and he started running through the forest.

The two approached a dark castle and the undead teen stepped inside before setting Star down and looked over her ankle, "Okay you hideous bloodsucker, what makes you think I'll trust you!" the Vampire looked up, "You're a monster and…my family hates monsters…and I'm a monster…part monster and-"

"Why don't we start by introducing ourselves and then we'll go from there,"

Star groaned and shook her head, "Whatever. My name is Star Butterfly, and if it wasn't for the fact that a monster raped my mother, I would've been the next Queen of Mewni and-"

"Mewni? What uh…what's that?" Star looked at him in confusion, "I never heard of the country of Mewni. Is it one of those lost countries that no one has ever-"

"Wait…what are you talking about? Are you not from Mewni?" the Vampire frowned and shrugged his shoulders, "Where are you from?"

"Um…America?" Star arched a brow and the Vampire looked at her in confusion, "The United States of America? U.S.A…uh…California?"

"What dimension is that?"

"What…what do…earth, we're on earth and-"

"No, we're on Mewni…and now maybe you should start explaining who you are and how you go got here," the Vampire frowned and Star crossed her arms before wincing in pain and rubbed her ankle, "Ow…this hurts,"

The Vampire sighed and shook his head, "How about I take care of that ankle for you and while I'm doing that, I'll tell you everything you want to know," Star nodded as the Vampire began looking at her ankle again.

"My name is Marco Diaz, and about a year ago I was bitten by a Vampire," Star looked at him as he continued, "I know a few things about Vampires, like if you're bitten, you can very well be turned and…I was unlucky that happened. When I woke up, I was hungry and attacked the closest source of food, which were four of my friends, and I bled them dry.

Anyway, I heard people running towards me, and not wanting to be judged or anything else, I fled…big mistake on my end. A Vampire can't flee from its Clan, or else they'll be hunted and killed by that Clan. Anyway, I felt something knock me back and I woke up in these woods.

I've found this castle and been living here ever since." Marco sighed and stood up, "Wait here. That ankle needs to be wrapped up," Star nodded as Marco turned and walked away.

Star looked down at her swollen ankle and narrowed her yellow eyes, "What is he planning? Is he going to nurse me back to health and then bleed me dry? And why wouldn't he just do it in the forest while everyone was fighting those bats?"

"Maybe it's because I'm not like that. I felt guilty after I killed my friends, so I swore I wouldn't do that again to anyone," she looked up and saw Marco standing above her, a first aid kit held tightly hand in his hand, "And besides, I already told you that I wouldn't kill another monster like that,"

Star narrowed her eyes as Marco knelt in front of her, the first aid kit resting next to him, "Okay, so why are you helping me?"

"I wasn't going to sit back and watch an army kill you," Marco began wrapping Star's ankle and Star felt a cold sensation on her injured foot, "Keep this cold compress on. It'll help with the swelling," Star nodded as Marco sat down next to her and the two teenagers listened to the sounds of the nocturnal creature play their nightly music.

Star looked up at the undead teen and took a deep breath, "You know you're outnumbered here on Mewni, right?" Marco looked at her in confusion and Star shook her head, "Vampires haven't been roamed Mewni for centuries. They were eradicated from existence. And you being here is going to cause all sorts of trouble,"

"Nothing I won't be able to handle," Marco took a deep breath and shook his head, "I'm used to people ridiculing me. So what's the difference here?"

"The fact that Mewmans are incredibly strong and every knight in the Butterfly castle won't only be out looking to kill me, but you as well. Since you're the first Vampire in centuries, I'm sure my mom has a price on your head,"

"Again, nothing I won't be able to handle," Star sighed before wrapping her arms around herself and lightly shivered.

Marco sighed before taking his hoodie off and wrapped it around Star. Star looked at him with slightly narrowed eyes, "It's clean. I wash it every night," Marco stood up and frowned, "Use it. It'll keep you warm until I build a small fire," Star hummed as she slightly nodded and held the hoodie close to her as Marco turned and walked away.

Star frowned and hugged her knees to her chest, "Why would they wait this long before doing this? If mom didn't want me, why would she…and that Vampire. What's his deal? Is he lying to me until I fall asleep and then he'll bleed my dry or-"

"You're reading too many fairytales," she jumped slightly and looked up to see Marco standing over her, a bundle of sticks in his arms, "Sorry, didn't mean to scare you."

"Jesus…how do you-"

"Inhuman speed, I managed to collect some firewood without a problem." Star frowned as Marco sat down and began building a small fire. He looked back up and shook his head, "And like I said, I'm not going to kill another monster. I'll go out and hunt for some field mice, or I'll hunt until I find a decent target."

"Right…I'm sorry, but…I've never met a Vampire before…or anyone outside of the Butterfly castle for that matter. I've been trapped in the dungeons all my life and they decided to play a little game and chase me through the forest."

"And they did they did that because your mother was raped by a monster, with the end result being you?" Star frowned and slowly nodded before Marco hissed, "I'm going to…idiots!" Star looked up as Marco walked towards the window and stared out at the forest, "I'm going to hunt them down and drain every last drop of blood from their bodies for doing-"

"Don't bother," Marco looked back and Star shook her head, "Like I said, there hasn't been a Vampire on Mewni in centuries, and my mom most likely put a price on your head, so the guards will out looking for you. And besides, we're in the denser part of the forest, so I doubt they'll find us," Marco frowned and looked up at the night sky, his arms crossed and a hardened look crossing his face.

Okay, this first chapter may seemed rush, but this is the first time I've written a MonStar and Vampire Marco at the same time. This is going to be rated for reasons and those reasons will come to light in later chapters. As always enjoy everyone and please let me know what you all think.