I had this idea randomly after reading a Halo crossover with Phineas and Ferb. (It's amazing by the way, you should check it out). And the idea of Master Chief and a kid became a liking in my head. Although, she's a teenager (thirteen actually). And is also my favorite version of my OC I've come up with (her name is Nafalis in case you don't know). This version is also the closest to the original idea I had for her.
This story is a time travel story just so you know. You'll figure the rest out later. The beginning is kind of like the crossover I read. At least, with the whole wormhole thing, but you don't see it from Cortana and Chief's point-of-view, you see it from hers. Anyway, enjoy.

The moon shone brightly over the small town of Sicawan. Two small children, a brother and sister, ran through the town giggling with each other before entering their house where the candles lit up the kitchen and small sitting space. A few candles sat unlit in their owners' windows and a slight breeze entered the houses and the candle sticks rattled against the windowsills they sat on, the lit candles' light flickered at the wind's attempt to blow it out. A few more candles were blown out as more families decided to sleep. By the time the moon had come up above the mountains to the east every single house was dark. All except the tiniest house the sat by itself by the river, this house stayed lit with one candle sitting on the kitchen windowsill. Being a bit farther from the town the small light did not bother any of the sleeping families whose breathing was beginning to slow down to the rate of rest.

Said small house had one bedroom, tiny sitting room, and kitchen. The bedroom had barely enough room for the bed and small chest that rested near the end of it. Inside the chest were resting clothes, day clothes, and rough leather clothes made for hunting, although they were much to big for the house's owner. The sitting room had two chairs, a table, and a box with five different books. In the kitchen was a stove, sink, a small place to cut, and a little table to eat at. Lots of the children spent their time playing around this house and learning from the girl that lived there. She taught them what she could offer to teach them at such young ages.

The young girl to whom I am referring too is named Nafalis. Nafalis is a very graceful person. She is also kind, brave, and soft spoken. Nafalis doesn't talk much, but she is not afraid to speak the truth, even if it hurts. Although, she is prepared to lie if she has too. Nafalis, age thirteen, is very wise for her age and is a fantastic fighter. No one knows where she comes from or how she got here. All they know is that she was very helpful in the dry season when food was scarce and taught their kids how to hunt and defend themselves. And in the war that was consuming the land, they may need that knowledge. Although, they do not agree with the stories she fills their heads with. Nafalis doesn't tell stories often because the parents do not like them, but on nights when wolves howl and the children shake with fear, she lets one slip through her lips.

Although, tonight no wolves howled and every child was sound asleep in their beds. This left Nafalis with some time to herself. She sat on the roof of her small house and looked up at the large moon of their land. This land does not have a name, which Nafalis found odd, but it was very colorful and the people in it were kind. Well, everyone except for that horrible dictator and his men. I'd tell you his name, but no one speaks his name. It is considered a curse to say it and if you do you will live a most unhappy, and dreadful, life. So I shall not speak it now.

Nafalis stood up and looked over as something streaked across the sky. It was quite large in size by what Nafalis could tell and covered in fire. She narrowed her eyes and hummed in thought. She turned to the village. When she came here the people were afraid of her, called her a demon and a witch. But once they came to trust her and she taught their children she had come to care for each and every one of them. She felt like this town's protector, and thought it her job to discover what the thing was and make sure it wasn't a threat. Nafalis grabbed onto the roof's siding and flipped onto the grass below without a sound.

She opened her door and reached up to the wall beside her to snatch her swords. She attached them to her back and quickly blew out the candle. Darkness filled the room and she silently shut the door as she walked out. She paused a moment to glance over to the village before looking over at where she had seen the thing land. She narrowed her eyes again. Whatever this thing was it had better not bring her town harm, for if it did it would have to face her wrath, and the wrath of this particular teen was not something anything, or anyone, would want to face. Nafalis took a deep breath and towards it. Her feet made no sound as it made contact with the land on the other side of the river and she continued running.

...

Nafalis stopped in her tracks and looked up at the huge hunk of metal that lay before her. Smoke came off of it as if it were a flame, although none were lit. Nafalis narrowed her eyes curiously. On the edge it read: Dawn. She wondered if that was supposed to mean something. She shrugged and decided to get closer. Her feet and legs pushed her forward towards the metal - um, thing. She stopped and ducked behind a rock as a figure walked out of the smoke. She poked her head over to look at it. It appeared to be a metal man with a mirror for a face. She narrowed her eyes again in thought. No, it was a suit and a mask. But they looked so strange and far beyond anything Nafalis had seen in her short, but well lived, lifetime.

Nafalis took a deep breath and took out her swords, although she knew that they wouldn't do any damage, but they made her feel safer as she stood up. The metal man turned to face her and took out a weapon, which he aimed at her. Nafalis didn't even flinch as he did so, but instead stared at him with no fear in her eyes. They stayed like that for a long moment, just staring at one another. Neither one dropped their weapon or dropped their gaze. Nafalis knew a true warrior when she saw one, and this was it. He held his weapon with such precision it almost looked graceful, he didn't flinch or look away, but most importantly he didn't fire his weapon. The reason this made a true warrior is because he didn't know if she was a threat or not, so he did not fire, or throw, his weapon.

Nafalis narrowed her eyes at him and lowered her swords, showing she did not want to be an enemy and was friend, not foe. The metal being didn't move and this worried Nafalis a bit. Was he waiting for her to lower her guard so she could be shot? Nafalis wanted to raise her swords again, but knew that it would only make things worse if he wasn't going to shoot her. The being tensed for a moment before lowing the weapon and attaching it to its hip. Its hand rested on the weapon, asking her to sheath her own weapon. Even though she didn't want to, Nafalis sheathed her swords and set her arms at her side. The being took its hand away from the weapon and headed over to her. Nafalis tensed as he stood only five paces in front of her.

He was at least seven feet tall, and he was either extremely well built, the suit made it seem that way, or both. For a moment they stood studying each other in silence. Both recognized the other as warriors with standerds and as friends, not foes. The man took two respectful steps back and nodded to her. Nafalis nodded back. A man of few words, interesting.

"My name is Nafalis," she told him.

"Call me Chief," he told her. Nafalis nodded and looked towards what he had come in. She gave him a raised eyebrow. "My ship crash landed. What planet am I on?" She raised an eyebrow in confusion. What planet? Was this man nuts?

"Planet? Why, Earth of course. Where else?" Her eyebrows knit together in confusion. What was he talking about?

"What year is it?" he asked quickly. Nafalis took another step back, something wasn't right, not right at all.

"The year 203," she answered. "Why are you asking such questions? Are you some sort of traveler of time?" Chief shook his head and walked away without saying anything else. Nafalis narrowed her eyes. Something about him sent shivers down her spine, she felt somewhat connected to this man, and this made her conclude to follow him. So she did. Chief did no protest as she walked behind him into the woods. "You're going the wrong way." Chief stopped and turned to face her. She had her arms crossed and a blank expression covering her features.

"If you go that way you'll run into the dictators guards and you'll find yourself in a cell with your armor being ripped from your person. If you wish to stay a secret from the world until you figure this out, come with me." Chief didn't question her as she turned and walked away, but instead decided to take her up on her offer and follow her to where she lived. She turned to face him and he took a step back. "You will not be a threat to my town, will you?" Chief shook his head. "Good." And with that she continued to lead him to her home.

...

Chief looked at the small town before him as Nafalis walked into the small house. She didn't really like him, he sent shivers down her spine that told her to kill him on sight. But he had set himself up as a friend, so she would treat him as such. She thought a moment. He was going to attract to much attention in that suit of his. He'd have to remove it and wear something else for the time being. She walked out of the house and saw him still standing where he had been two minutes ago. She grumbled to herself. He wasn't going to be easy to have as a friend. Hopefully it wouldn't last to long.

"Chief," she said. He turned to her as she walked up to him. "All right, I can allow you to stay here. Under one condition, you cannot wear your suit. You'll attach to much attention with it. You can take it off, yes?" Chief didn't respond. He didn't even nod. "Well? If you don't I'll have to send you on your way." Chief still said nothing. Nafalis glared at him for a long moment. His shoulder moved irritatedly before he nodded. "Good. Come on." She led him into her small house and told him to wait a moment as she walked into another room. Nafalis walked out with the leather clothes that were much to big for her.

"These should probably fit you," she told him. "So, how do we remove this armor exactly?"

That's all for now. I may or may not continue this story. It depends on how many views, reviews, and followers I get. But, let me know. I may continue it anyway because I will want to, but I don't know. Anyway, please review!