So, I know that there have been a few the 100 and ATLA/LOK crossovers but I wanted take a shot at it. I think what's different about mine is that I made Lexa the Avatar and this is more her story than Clarke's, even though Clarke will be a major character in this story, too. After watching the 100 and reading some fics, I just noticed so many parallels between Lexa being Heda and the life of an Avatar so I just had to write something! I also noticed that most the 100 and ATLA/LOK crossovers only had like a few chapters but I want this to be a full-on story because I like long stories :)

I'm just going to tell you from the start that not everything will be straight from either Avatar series since I've only watched a few episodes here and there from both and I may be a little rusty on my knowledge, so I may make some things up or fill in gaps, but most of it will be straight from both series.

And lastly, I'm going to try and make this story easy to understand for people who haven't seen either The Last Airbender or Legend of Korra. My story is taking place in the ATLA and LOK universe but I'm pulling characters from the 100 into the universe. Here are a few pointers for the newbies:

- In this universe, there are people who can wield four elements: water, earth, fire, and air, and they are called benders. Ex. Earthbender.

- There are four nations composed of people who can bend these four elements: Water Tribe, Earth Kingdom, Fire Nation, and Air Nomads

- The Avatar, which is Lexa in this story, can wield all four elements and she's the only one who can do this. Everyone else can only control one element.

- The Avatar is supposed to keep balance in the world and is the bridge between the physical world and the spiritual world (this sort of changes in LOK but for now just know that the Avatar is special)

- The Avatar is reincarnated, much like the Commander on the 100 is, so they have a bunch of past lives

- ATLA tells Avatar Aang's story and how he defeated the Fire Nation who was basically acting like Nazi Germany and killed off the entire Air Nation, which were Aang's people and that's why the first series is called The Last Airbender

- LOK tells Korra's story and the only thing you need to know for now from that story is that Aang created a place called Republic City where all people from all nations can live in harmony, so it's basically the US of the Avatar universe. And Korra opened the spirit portals so that both humans and spirits can use them to travel between the physical and spiritual worlds.

I hope I covered everything important, sorry if I left out anything blatantly important, I'm super tired right now and I'm thinking of these off the top of my head! Which is why I HIGHLY SUGGEST that you watch both series (if you have Amazon Prime all of ATLA is on there for free and so is LOK up to the 3rd season and then you have to pay after that, I believe. I'm sure there are anime websites where you can watch both shows for free too, but Prime is a little more organized and less sketch) if you haven't already or at least do some basic research. And finally, to my story!

Chapter 1—Humble Beginnings

It was a scream that pierced her ears and her dream, effectively shocking her out of a deep sleep. As an Avatar six months into training at just 12 years old, Lexa had already been told many times by her mentor that she needed to be alert and ready at all times, that there was no room for slowness or laziness, but no amount of advice would have prepared her for what awaited her outside her room that night.

"Lex, did you hear that? It sounded like mom…" her eight-year-old brother Aden said, sitting up in the bed, and even in the dimly-lit room, she could see the worry in his eyes and it filled her with dread, too.

"Shh, I'm going to go check it out, but you stay here," Lexa said, swinging her legs out of the bed and quickly standing to her feet.

"But what if you need help?"

"No! You stay here no matter what, do you under—" There was a noise that resembled a vase breaking and another scream. Lexa's body moved on auto-pilot towards the sound of the chaos. She swung the door open, scrambling through and closed it before her brother could follow after. She then reached for the nearby desk in the hall and pushed it to the door, hoping to lock Aden into their room, at least until she could figure out what was going on.

As she scurried down the hallway, her slumber from being awoken too suddenly began to slip away and her senses quickly became more heightened. There was more yelling coming from the kitchen and family room area, and even though her body seemed to move on its own, her mind, or rather her fear, was telling her to go back and hide with Aden. She had never felt fear like this, but she had to be brave. She was the Avatar. The hallway began to get gradually dimmer so she created a fireball in her hand as a source of light, but just as she came to the end of the corridor, she almost wished she had no way of viewing the scene before her.

"Lex-a," her father gasped, as he lay on the ground with blood consuming his shirt.

"Father…" Lexa barely managed to choke out. "Wh-what happened?"

He only shook his head and uttered his last words to her. "Just run."

Lexa watched on as the life left his eyes and she was brought to her knees, shaking with emotion. "No, father, please!" She shook his lifeless form as her whole body throbbed in panic. She let out another yell for his attention when a foreign voice rang from outside the room, "There she is. Get her!"

Those words were enough to distract Lexa from her father and bring her focus to the sound of footsteps pattering towards her and the ring of ice forming around her. Waterbenders! No, no, no, they found me…

She stood frozen as an icy claw latched onto her leg, keeping her in place. A shriek escaped her lips at the sensation and she barely took any defense as her attackers came into view in the small room. But before they could finish the job, blazing whips of fire shot out throughout the room, catching everyone off guard and the sound of Lexa's mother's voice rang out, "Lexa!"

She gasped. "Mom!"

"Try to get away from them," her mother yelled back, knocking both attackers off their feet with her favorite dragon's tail move.

"I can't. My foot is stuck," Lexa cried, as the attackers clumsily found their footing and one of them came at Lexa again while the other defended against her mother.

"Use your firebending!" Her mother told her as a lash of water whipped at her. Before then, Lexa was having a hard time getting her mind to work around her fear, but at her mom's words and the sight of her father's dead body beneath her, she suddenly got into focus. Everything her firebending master Anya had taught her in the last six months came rushing back to her. With new strength, she lashed out at her approaching attacker, throwing a wave of flames at him. But he was quick to dodge the fire, twirling high in the air above the flames and over to Lexa.

She managed to move out of the way to not get a foot to the face, but not fast enough to avoid another icy grab at her feet, chaining her to the ground. She gasped in panic as her attacker's whip of water reformed into a shard of ice and in the next second, a searing pain shredded through her arm as the shard pinned her to the wall. She cried out as tears clouded her eyes and again she was at a loss for action or thought.

Lexa blinked the water away from her eyes and saw that her attacker was no longer in front of her but in fierce combat with her mother. The pain has devoured her whole arm and she finally knew how it must feel to be on the other end of a firebender's attacks. I have to fight!

She took deep breaths in and out, straining against her icy captor and at last brought her hand up to the shard, melting it away. She collapsed on the wooden floor, her knees hitting the ground hard and her stomach quenching at the amount of blood all around her. She didn't know who it belonged to anymore, her or her father, but her thoughts were broken again with another earth-shattering scream. When Lexa looked up, she seemed to be viewing everything from far away, as if it was part of a dream or that she wasn't really there. The scene of her mother pinned to the other side of their family room by icy shards through her stomach and chest didn't look real. This was something out of a horror picture. It was a nightmare. It couldn't be real. So, Lexa shut her eyes and muttered repeatedly to herself, "Wake up, wake up, wake up…"

"You all put up such a good fight. It was truly an honor." Lexa looked up to see who was violating her chant, and it was her attacker, the one who had pinned her to the wall. The one who had killed her mother. "But you're coming with me."

Lexa cried out, wanting to get up, needing to, but she couldn't. Her body refused to. The man chuckled at her with a devilish smile smeared across his face. Why am I not waking up? This can't be real, it can't be!

He started toward her again but before he could take even three steps in her direction, a ferocious blast of fire soared through the air, scorching his head. In seconds, his pasty flesh had been transformed to dark ashes and in the next moment, his body toppled to the ground.

Aden's dazed figure was revealed to Lexa as the dead waterbender tumbled to the ground, his gaze slowly falling from Lexa to their father's lifeless body.

"Aden!" Lexa panted. "Are you okay? Did you…" She faded off, not knowing how or wanting to finish that question. Her scrawny, goofy eight-year-old brother who spent most of his time playing with toys and eating too much candy for his own good, had not only just witnessed their parents' deaths, but also caused one himself.

Even in the dim light, she could see his eyes beginning to water but just as she opened her mouth to reassure him, another person burst into the room. Lexa's heart rate spiked in terror. No. You won't take Aden, too.

Her body was re-energized and she sprang to her feet into a fighting stance and with a plume of fire dancing around her hand at the ready. But before she delivered the blow, she heard a familiar voice come from the person. "Aden? Lexa? Oh, thank Raava…"

"Anya?" Lexa breathed a sigh of relief at seeing her mentor and a group of more firebenders filling the room. But the relief was short-lived when the newcomers noticed the lifeless bodies around them. They made no comments, but their responses were written all over their faces.

Anya turned to one of the guards and sternly commanded, "Lock down the perimeter. No one gets in or out. And do a full search of the village. I want every inch covered. I think I took down the last one," she says, gesturing toward the headless waterbender. So, it wasn't Aden. That was probably the only bit of good news Lexa would receive that night. "But we need to be sure."

"Yes, ma'am." The guards nodded and were then rushing out the way they came. Lexa listened to their determined footsteps fade away, leaving her with her brother, her mentor, and death all around. Her gaze fell back onto her mother's limp figure up on the wall. Why wasn't I quick enough? I was right here and I froze. What kind of pathetic Avatar am I?

She didn't even realize she was crying until a hand made contact with her shoulder. "Lexa," Anya's voice softly said. When Lexa didn't look up, Anya tried again with a firmer tone but with the same gentleness in her grasp. "Lexa, look at me."

Lexa glanced up to her mentor but Anya's face was distorted, her expression slowly transforming into a foreign one. "Mistress Lexa!"

Lexa shot up startled in her chair and the servant girl who awakened her took a few steps back herself. She looked up at the girl who was probably only a few years older than her. They had met before but the older girl's name escaped her. "Uh, yes…" Lexa responded groggily, running her fingers through her hair. She was in one of the quarters of the lower deck of a ship. Lexa didn't remember falling asleep here but she knew she had been exhausted and since the couch she had knocked out on was more comfortable than any bed she'd slept on lately, she didn't blame herself.

A timid expression overtook the servant's face and she smiled politely. "I am sorry for the abrupt disturbance, Mistress. We will be arriving shortly but Master Titus has requested your presence on the deck."

Lexa nods and tries at a smile of her own. "Thank you."

"It has been a pleasure to be at your service," the girl says in a sweet voice, her cheeks filling with a deep pink. Before Lexa can respond, the girl gives a subtle bow and scrambles out of the room. Lexa never knew how to respond to people's attraction toward her. She wasn't all that experienced in love and wasn't given many opportunities to experience it due to her training. She had figured out years ago that she seemed to only have a desire for other women after a few moonlit nights with a couple of Ba Sing Se's most beautiful girls, but she still had yet to experience real love.

Her stomach began to fill with warmth at the look the servant girl gave her. The girl was very beautiful with long black curls and greenish eyes that belonged to the people of the Earth Kingdom, but when she remembered that the girl told her she had to meet with Titus before they arrived at their destination, she shoved down the forbidden feeling, reminding herself of her self-imposed motto.

"Love is weakness," she whispered to herself, and if that wasn't enough, the nightmare that she just woke up from lingered stubbornly. It had been six years since that horrific night, but her arm throbbed occasionally as if it too still suffered from nightmares. She still had Aden, who was back in the Fire Nation, attending the most prestigious academy in the country, she had Costia, her childhood best friend, and she had all of her mentors and masters, and that was enough. They were all she needed and she worried enough about them. Anyone who was close to her and anyone who knew who she was was in constant danger. Ever since the night that assassins who came after her and killed her parents in the process, it had been imperative that Lexa's Avatar-status be kept on a need-to-know basis, that is, only her brother, Costia, who had found out when Lexa found out, her masters, and members of the White Lotus knew she was the Avatar. The rest of the world knew that there was an Avatar out there and that she had gone into hiding because there had been an attack on her life but they had no idea of her identity.

Queen Nia of the Southern Water Tribe decided to turn the other half of the Water Nation into an oppressive, tyrannical state shortly after Avatar Korra's death 23 years ago. The next Avatar, an earthbender and the one who would've stopped her, was killed by assassins just shy of his fifth birthday. It is assumed that the assassins were Water Tribe but there was no evidence so the Southern Tribe wasn't confronted. But then it happened again with Lexa. Only six months after finding out she was the Avatar, she was already being hunted. The rest of the world knew that Nia was an oppressive ruler, but since the South was very autonomous and hardly traded with the outside world, there was no order to tell a ruler how to rule over their country, and her actions didn't affect other areas of the world, no one was in any rush to come to the Southern Tribe's rescue. No one seemed to mind that the Avatar was being hunted either. Ever since Avatar Korra's rule, things had been fairly peaceful throughout the world. It was as if they no longer needed the Avatar. But it was the Avatar's duty to make sure that there was peace and harmony for all, including those in the South, and if Lexa had to remain in hiding until she mastered all four elements and was ready to face Queen Nia, then so be it. She would get justice for them and she would get justice for her parents as well. That's why she was headed to the Northern Water Tribe.

Titus stood at the bow of the ship, his hand on the railing as he overlooked the deep blue ocean. His orange and yellow robes flapped wildly about him in the sea breeze but his attention stayed on the approaching strip of icy land that would be Lexa's home until she became a fully realized Avatar. This is how it had been for the last six years. In the beginning, right after her parents' deaths it was a lot more chaotic. Since they didn't know what Queen Nia's next move was or if she had more assassins on the way, for several months, Lexa and her brother had been shuffled all around the world to different safe houses. Once the White Lotus noticed things had calmed down, they allowed Lexa to continue her Avatar training. But since they didn't want to be too predictable, after mastering firebending with Anya when she was 14, instead of sending Lexa off to the Air Temples to train in accordance with the Avatar cycle, she was sent to the Earth Kingdom to learn under the guidance of Gustus, a former general in Ba Sing Se's army. Two years later she was sent to the Eastern Air Temple to train under Titus, and another two years later at 18 years old, she was now being shipped off again to the best and safest place where she could learn waterbending.

Lexa came up on Titus's right, training her gaze on the great icy nation that stood hidden behind mighty walls of ice. It was very secluded but Lexa knew that the North was not a nation to be trifled with. Lexa remembered the nearly 200-year old story of the great siege of the Northern Tribe, when her native nation led by Admiral Zhao had attacked the North in a futile attempt to take out one of the last superpowers in the world and to stop one of her past lives from finding a waterbending master. It had been quite a crazy and unfortunate situation for both sides. Zhao and many of his soldiers were killed in the battle, the Moon spirit in the form of a koi fish was slaughtered by Zhao and in order to bring it back, the princess of the North had to give her life back to the moon, but craziest of all was when her past life, Avatar Aang, became so overcome with emotion and anger at the murder of the Moon spirit that he merged with the Ocean spirit, the Moon spirit's companion, into a giant water creature and destroyed the fire nation fleet. At the time, Aang had only been 12 years old and he only had one element mastered, yet he had still single-handedly defended a nation against an entire army. He was a great avatar. But when Lexa was 12, she couldn't even save her parents from a pair of waterbenders. She vowed that she would be better the next time a threat came.

Lexa folded her arms together, already feeling antagonistic toward the biting, crisp air. This below zero temperature would definitely be an adjustment.

"We will be landing in about an hour," Titus said. Lexa nodded, feeling excited but nervous like she did whenever she came to a new place. This time she especially had reason to be. The last three times, she had trained with her masters one-on-one, but this time she would be training with a small group of waterbenders her age. Even though she was solely focused on completing her Avatar training, she was looking forward to being around people her age. She hadn't had that kind of interaction since this whole Avatar thing started. She only got to see Aden and Costia twice a year.

"Shall we go over the rules again?" Titus asked, but it sounded less like a suggestion and more like a command. He was never not in teacher mode.

Lexa rolled her eyes. "I know the rules. I've been through this twice already."

"But this time is different. You'll be interacting more closely with other benders and since it's unusual for the water tribe to acquire new residents, they'll be watching you closely. You need to be more careful than before."

"I will, Titus. Stop worrying, that's how you lost all of your hair in the first place," Lexa said with a smirk.

He frowns at this. "I am a monk, it is required that I have a hairless head. I can still grow hair."

"It was a joke, Titus. You know, humor? Raava knows we all need a little of that in our lives," Lexa says, thinking of how intense things have been for the last six years. She was always deeply engrossed in her training. She hadn't mastered the elements as fast as Avatar Aang but her masters and the members of the White Lotus were beyond impressed with her progress. It had taken decades for most previous Avatars but she was on track to be finished in another two years. The desire to take down Queen Nia and avenge her parents is what pushed her through the hours and hours of brutal training. Every drip of sweat, every bruise, every tear shed on her pillow after a day of ferocious training would all be worth it when she got her sweet vengeance. Queen Nia would bow before her and she would repay her for all she's done, one scream at a time.

"The rules, Lexa?" Titus persistent order called Lexa out of her dark thoughts. She had to shake her head to completely rid her mind of them and with an annoyed sigh, she said, "No telling anyone I'm the Avatar, no discussing anything Avatar-related with anyone, no bending of the other three elements in public—"

"Or in private," Titus sharply interjected. "You will take no chances."

Lexa turned to him, raising an eyebrow. "But if I don't practice the other elements, won't I get rusty?"

"You will take frequent trips to Air Temple Island. You may practice there." Titus decided to stay at Air Temple Island for the duration of Lexa's Avatar training. Since airbenders were the most spiritual of the four nations and especially since Titus was the great-grandson of Avatar Aang, he felt that he had a particular duty to protect and serve the current Avatar.

"I get a vacation? Wow, I really am upgrading," Lexa said in her lackluster tone.

The ship continued to glide along the freezing waters and like Titus predicted, they arrived in the next hour.

So, did you like it? I'm already working on chapter 2 so if you want more, please review and share the story to get the word out. Thanks for reading!

Btw, I changed tenses in this chapter. Last chapter I wrote in past tense but from now on I think I'll write in present since that's what I'm more comfortable with.