AN: I published this on AO3 months ago so most of you may have already seen it. But then it hit me that I never crossposted it here, so here you go. Better late than never, right?

I am not sorry I wrote this. Not sorry at all.

For the prompt: Arthur and Lyanna raising Jon together

One.

Three members of the Kingsguard came down the Tower of Joy to defeat Eddard Stark and his companions. But only one makes it back.

When Lyanna sees the blood marring Arthur's white cloak, her composure breaks and she starts to cry. She knows what this means. There will be no victory for House Stark. Not now. Not ever. Now there is only Lyanna - broken and bloody and half the wolf she once was - and Benjen - shy, calm Benjen who is so far away he might as well be lost to her forever. And Jon. At least she still has Jon.

Arthur Dayne goes to her with grief-stricken eyes and hands meant to hold and comfort her, but Lyanna stops him with a look. "Don't," she says, her harsh voice a stark contrast to the odd way her body keeps on trembling.

There is much that needs to be done, but Arthur nods and allows her this one moment to grieve. He hates seeing Lady Lyanna cry. Has hated it since the first moment he saw Rhaegar break her heart with his cryptic words of three-headed dragons and long lost prophecies. It reminds him of all the dark nights he spent outside Queen Rhaella's chambers, guarding her against imaginary threats, all the while pretending that he isn't forsaking one vow for another.

He could have saved Lyanna Stark a long time ago, before her family burned at King's Landing, before Robert started a war in her name, but Arthur Dayne is nothing if not loyal.

Today he will bury his slain brothers and mourn the dead. Tomorrow, he would take Lyanna Stark and Rhaegar's only living heir across the Narrow Seas and live.

The Kingsguard do not run. They do not hide. But Arthur need only be reminded of the promise he had made his prince ("Guard them with your life, Arthur," he remembers Rhaegar telling him, not knowing that those are the last words he would ever hear him say) in order to erase any lingering doubts he might have.

He already failed Prince Rhaegar once, when he allowed him to ride off into battle without his trusted knight and comrade by his side. He would not fail him again.

Two.

They arrive at Essos at the break of dawn. The whole thing is uncomfortable, pretending to be a half-Lyseni in search of a new home for his wife and newborn child, and nothing in Arthur's training as a knight could have ever prepared him for this moment. He hates hiding Dawn, hates the sensation of not wearing armour, of wearing a cloak that isn't white, but he knows he can never voice these thoughts out loud. Not when Lyanna Stark is standing just a foot away from him. Lyanna Stark, who lost her brother and her father to a mad king's whims. Lyanna Stark, who is now forced into exile with a man who is both her captor and protector. Compared to all the misfortune she has suffered, Arthur knows he has no right to complain at all.

He suspects Lyanna likes the situation even less. She does not want to trust him, Arthur can see it every time she hesitates before she lets him touch the babe, but in this strange new world, she has nobody else but him.

So she smiles and calls him Art and pretends to be his loving wife just long enough to deflect suspicion, but when Arthur insists that she give herself a new name, Lyanna refuses. "You will call me Lya," she says.

Arthur tries to reason with her, but on this she would not be moved.

"You and your prince have taken everything from me," she tells him. "My name is the only thing I have left. You will not take it from me."

Three.

Lyanna soon gets used to life as a sellsword's wife. When lesser women would have given up and ran away, Lyanna falls to her role with ease. Finally freed from the constraints of life as a noble and all the responsibility that it entails, Arthur watches her bloom. It is an astonishing sight to behold.

He used to wonder what it is about this Stark girl that makes men want to throw away their honour and die for her, but now… Arthur gets it now.

Four.

There are times when he starts to lose himself, when he would feel less like a knight and more of a failure, and the ghosts of the past would haunt him so. Those times are few and far in between, but when it happens, Lyanna is always quick to bring him back to the present. She would cup his face with gentle hands and tell him, "You are Ser Arthur Dayne, the greatest knight that ever lived. You are the Sword of the Morning. Remember that."

Then she would unwrap Dawn from its hiding place and present it to him, and though the sword is heavy in her hands, never once does she complain.

Arthur wonders when she started thinking of him less as the man who killed her brother and more as the man who would give up his life to protect her and her child.

Five.

Jon grows up quickly, too quickly, if Lyanna's comments are any indication. He is a sweet boy, with none of his mother's quick temper and impulsiveness, and there is something about his solemn face and the quiet manner in which he carries himself that reminds Arthur eerily of Rhaegar. But his appearance - from his dark brown curls right down to his stormy grey eyes - is all Stark. He can't tell who is more grateful for it - him or Lyanna.

By the time the boy turns four, Arthur no longer has the heart to correct him every time he slips up and calls him "Father."

Six.

It isn't long before Arthur begins teaching them the way of the sword. At first it's just Lyanna - stubborn, persistent Lyanna who bribes him with stuffed green peppers, like the kind they used to serve in Dorne, until he's forced to cave in to her demands - but when Jon is deemed old enough, he starts training him as well.

The boy is a quick learner, and Arthur takes care not to coddle him, the way Prince Rhaegar was coddled at Summerhall, and the way Prince Aegon would have been coddled, had he lived long enough to survive knighthood. They train from morning till dawn, and soon, under the legendary knight's careful tutelage, Jon Targaryen becomes a force to be reckoned with. Not enough to defeat him in single combat, but enough to make him proud.

"You are so strong, Father," Jon tells him one day, just moments after Arthur disarms him with a particularly difficult move. "Will I ever grow up to be as strong as you?"

"If you keep up with your training and remember everything that I've taught you, perhaps one day you shall be strong enough to defeat me."

Arthur doesn't tell him that when that day comes, he would be all too glad to hand Dawn over to him.

Seven.

He doesn't want to admit it at first, but he has grown to love life as a Westerosi exile. He still misses home, still longs for Starfall, for the moment when he could don his white cloak again, but there are other things about this new life that he has learned to appreciate. Lyanna Stark's smiles, for instance. Sometimes, when she smiles at him just so, he finds it hard to remember his vows. He won't allow himself to cross that line - he's too much of a knight for that to happen - but it isn't the first time he's been tempted.

And then there's Jon. There will come a time when he and Lyanna would have to tell him about his real parentage. Even if Lyanna changes her mind later on and refuses to leave the life they've carefully built, Arthur knows it is his duty to tell Jon about Rhaegar and the destiny that awaits him at Westeros. They would have to leave the lovely cottage with the thatched roof behind, go home, and reclaim a throne for a king the realm never even knew existed.

There would be another war, but that doesn't bother him. The great Ser Arthur Dayne isn't scared of war.

What scares him is that he might not want to go back.

AN: I see a new ship on the horizon.

I completely blame my wonderful mutual on Tumblr for making me ship this pairing. Now I'm in pain because there are hardly any fics about the two of them around, and I want more.