a/n: i own nothing, i promise. everything belongs to bryke.

prologue:

demons run when a good man goes to war

night will fall and drown the sun

when a good man goes to war

friendship dies and true love lies

night will fall and the dark will rise

when a good man goes to war

demons run, but count the cost

the battle's won, but the child is lost

when a good man goes to war

-Steven Moffat

"Aang, you can't leave."

Aang wished that Katara would stop begging him to stay—she knew that he had to go. His children knew. It was foolish of him to stay in a comfortable life with his wife and children while the fabric of the space-time continuum was in such a state of disarray. "Katara," he began delicately, not wanting to leave any more than she wanted him to. "I have to leave. It's my duty as the Avatar to protect you, and Bumi, and Kya, and the little one on the way." His frown grew into a fond smile as he leaned closer to Katara's side and placed a gentle hand on her swollen stomach.

(He still recalled when she'd told him that she was pregnant for the first time, and how he had run around the island chanting something akin to "I'm gonna be a daaaa-dy, I'm gonna be a daaaa-dy" the whole while.)

A choked sigh escaped Katara's throat as she sidestepped away from him and crossed her arms over her chest. "What about your duty as a husband?" she spat, sounding angrier with every word that she threw in his direction. He didn't remember the last time he'd seen her so upset. "What about your duty as a father? Spirits, Aang, you can't just abandon us! We need you, all of us need you! Bumi is seven years old—he needs his daddy and so does Kya! She's only four! And how do you expect me to raise our newest child without their father?"

"I know, Katara!" Aang shouted, bits of his temper escaping him. Air swirled around his fingertips, and it took every ounce of willpower he had not to let his temper get the best of him. He couldn't go into the Avatar State now. "I know," he said again, his voice quieter. "Do you honestly think I want to abandon you?"

"You're certainly acting like it!"

"How can you say that?" Aang's heart felt like it had been crushed by a steel hand and he was sure that it showed in his expression. "How can you stand there and tell me that I don't love you or my children more than life itself?"

Katara's stoic expression crumpled like a paper bag and she rushed at him. For a split second he actually thought that she was going to slap him, but her arms enveloped him in a warm hug and he relaxed into it, feeling all of a child again. "I'm sorry," she murmured, pulling him down so she could press a quick kiss to his lips. "Spirits, I'm—I know it's your job, but that doesn't mean I have to like it."

"You liked it fine when it was you and me against the world, traveling through time and space," he said, injecting a bit of levity into their conversation.

Thankfully, Katara let out a small giggle. "Back then things were different," she said fondly, and he knew that she had just experienced the same trip down memory lane that he had. Of first words ("Want to go penguin-sledding with me?") and exchanging names ("I'm the Avatar." "But do you have a name?" "...Aang. You can call me Aang." "I'm Katara, and this is my brother, Sokka.") and saving the world together. "Now I'm an old married woman with two kids, a third on the way and a husband with a saving-people-complex."

"Hey, I take offense to that," Aang replied, not offended at all.

The silence between them was comfortable and was only interrupted by a door slamming open and two sets of footsteps running down the porch and small, pleading voices begging "Daddy, Daddy please don't go!"

Aang swore that his heart shattered into a million pieces as Kya, his little princess and the spitting image of her mother, leapt into his arms with the agility of an acrobat and threw her little arms over his neck. He felt something wet trickling down his neck that he was positive wasn't sweat. "Daddy, you can't leave," Kya whimpered. "I'm sorry for anything I did, just please don't go..."

"Oh, Spirits, honey." Aang had no idea where to even begin reassuring her. "It's not your fault, nothing is your fault..."

"Then it's mine, isn't it, Dad?" Before Aang knew it his arms were filled with two of his crying children. "Dad, I'm sorry for pulling Kya's hair and getting a bad grade on my science project and eating those egg cookies before dinner and—"

"Bumi, slow down, none of you did anything wrong, I promise," he said, kneeling so he could see eye to eye with his children. "You know that my job is important, guys. I have to save the world, and that means that I have to go for a while."

"C-can't you save the world from home?" Bumi pleaded, clasping his hands together. Kya, copying her big brother, did the same. Aang's heart broke a little bit more. "Please?"

"I really wish I could," Aang whispered. "But I can't." Pull yourself together, Aang, he could hear Kyoshi's gruff voice telling him. He sniffled. "But I won't be gone forever, I promise. It'll seem like five minutes, guys." Bumi and Kya nodded, reassured slightly, because they knew that Aang never broke a promise. "Boom, I need you to be a big man and look out for your mom and your siblings, okay? I'm counting on you."

Bumi snapped him a salute, looking absolutely serious with the prospect of his mission. "I promise, Dad."

"And Kya, I need you to be a good girl, okay, sweetie?" He didn't get to finish the sentence before the little girl affirmed his promise and gave him a a huge hug and a kiss on the cheek.

Aang stood up, knowing he couldn't put it off any longer. "Katara," he began, taking a last look at his wife, drinking in the sight of her. He never wanted to forget her, not as long as he lived. He wanted to say a thousand things to her, but if he had the rest of his life he wouldn't be able to describe all the ways that he loved her. They had had years together through time and space, and yet he found it impossible to leave her. "I love you to the moon and back."

"I love you more, Aang." Katara looked ready to cry again. "You had better come back, or I swear, I will track you down and drag you back here kicking and screaming. You hear me?"

"I hear you." A laugh escaped from him like a gust of wind. "I won't be gone forever," he told his family as Appa flew down beside him with a grunt. "I will be back before you know it. I promise."

He climbed on top of his sky-bison and took one last look at his family: at Katara, in all of her beauty even at four months pregnant, at Bumi, already accepting his temporary position as man of the house, and at Kya, his little princess blowing him kisses. "I love you," he called as Appa took off. "I'll be back soon, I promise!"

He never came back.

You see, it was not because he wanted to abandon his family. It was because of his duty, the reason of his existence.

So Avatar Aang, as he was called, fulfilled his duty and battled the incarnation of evil while missing his children growing up, while missing growing old with his wife. While doing his duty, he missed his friends and former companions growing old and moving on to the Spirit World—

...what's that?

Ah. You do not understand why it was his duty and his duty alone to fight evil.

My apologies, dear readers.

Allow me to backtrack.

Once upon a time, before humans came to be, before the formation of the Four Nations, when the universe was in its infancy, there were lion turtles. They lived in the Spirit Wilds and served as protectors of mankind by housing human cities on their backs. As indicated by the symbols on their foreheads, lion turtles showed affinity for one of the four bending arts (water, fire, earth, or air) and possessed the ability to grant certain individuals with the power to control the specific element to which they were attributed.

Those able to bend an element, as it was called, were granted the prominent title of Avatar.

And along with a specific element, they were granted the ability to travel through time by bending gravity and the space-time continuum to their will.

(The latter was an ability that the Avatars rarely used, but made for wicked games of hide and seek.)

Millennia passed. Avatars lived in harmony with their Spirit and human counterparts (who were unable to bend and were happy that way). One particular Spirit, Raava, the embodiment of light and hope, formed a bond with an Avatar named Wan, who had the power of fire. (Exactly what kind of bond they had differs from story to story.)

And then, dear readers, everything went to hell.

The embodiment of evil, called Vaatu, arose and spread lies and dissidence to the humans, who rebelled against the lion turtles, demanding to have the powers of the elements like the Avatars had. Their pleas were unsuccessful, and the humans raged, killing all of the lion turtles—or so they thought. One remained, the one belonging to Wan.

While the humans were initially sad at having lost their protectors, they quickly bounced back and created a civilization of their own—the Four Nations—and their children and grandchildren later forgot all about the lion turtles and the Spirits and Avatars and their strange powers.

Wan and Raava, on the run, never forgot, and spent the rest of their lives on the run from Vaatu, who was determined to hunt them down and let the world lose its last protector. He possessed certain Spirits to do his bidding, nicknamed Darkies by Wan.

But Vaatu and Wan could not avoid each other forever.

In a fierce battle, both were left mortally wounded. In an effort to keep Wan alive, Raava permanently fused with him on the Avatar's last breath, causing an anomaly to occur—Wan was now immortal. Whenever wounded gravely, his body would change, and he could go on living forever and ever. He could change his age, but never his appearance. That was Raava's bidding. Upon death, the Avatar Spirit caused the Avatar to reincarnate into someone able to bend a new element, dictated by the cyclic order: fire to air to water to earth, for always and eternity.

As always, there was a catch. The reincarnation cycle could only be broken if the Avatar was killed while in the Avatar State (a defense mechanism designed to empower the Avatar with the bending abilities and knowledge of all the past Avatars), Raava was removed from the Avatar and destroyed, or the Avatar Spirit was compromised by a spiritual infection.

Vaatu, unfortunately, had the same idea, and fused with a human, giving himself the ability to regenerate as the Avatar would in an effort to finally, one day, kill him.

Raava did not disappear—she was always there for the Avatars after Wan. Not as a Spirit as she once had, but as an animal companion. Yes, dear readers, Aang's Appa was Raava, and Aang himself was Wan, many centuries into the future.

The Avatar, on every reincarnation, chose a new name for himself or herself. They preferred to travel in time with companions in order to feel less alone. Only their companions could call them by their chosen names—everyone else must christen them as "Avatar".

The precise second that Avatar Roku (gifted with the powers of fire) regenerated, he and Raava were kept in suspended animation (read: trapped in an iceberg) for a hundred years by Vaatu. It all seemed bleak. Humanity began to dissolve into war. Vaatu began to think he had won.

And then two siblings from the Water Tribe, Katara and Sokka, discovered the Avatar's newest incarnation.

(Ah, you are starting to understand, are you not? You need not worry, my story is nearly complete.)

Raava regenerated into a sky-bison and was nicknamed Appa. The new Avatar, gifted with the powers of air, took the name Aang and assumed the age of a twelve year old in order for him to better fit in with his new friends. With the help of a blind heiress with nerves of steel, a runaway prince looking to regain his honor, a fan-brandishing warrior, a master swordsman and a kind healer in training, Aang helped get the world out of the gutter and took his new friends on adventures in time and space.

Dear readers, you know what happens next. You know that Aang marries Katara. You know that they have three children. You know Aang abandons them to go and fight Vaatu's latest incarnation. You know that the children grow up without a father.

However, that is not the end of the story of the last Avatar.

But how can that be? you ask. How can that be when you've just told us that Aang never came back?

But that is just that, dear readers.

He never came back.

For this is not the story of Avatar Aang, bender of air. This is the story of his successor, the Avatar gifted with the powers of water. This is the tale of a girl not wanting to be branded by the glory of her predecessor. This is the story of a hot-headed teen, her polar-bear dog, and her companions.

This, dear readers, is the Legend of Korra.

end notes | you know, i told myself that i wasn't going to write this until I was done with the second case of Illogically Logical, but my plot bunnies insisted. really, guys? a doctor who au of LOK? exactly how much of a fandom geek am i right now?

my thanks go to a good friend of mine for helping me transform this fic from a rabid plot bunny to something resembling a fic. you know who you are and what i mean. so really. thank you.

unfortunately, i'm going to be gone for the next few weeks, meaning slow updates. i don't know how long this is going to be, but i do have a vague idea of where this is going.

so keep an eye out for updates on this, no matter how sporadic they may be i have never given up on a fic for this fandom and i don't intend to start now.

well, that's all for now, folks. review, fav, follow, raise my traffic stats—do whatever you need to do! and constructive criticism is, as always, greatly appreciated! :)