Author's note: Hail to all! Welcome, welcome to the tale of a descent from darkness into light and from light into darkness, the tale of a child turned traitor, the tale of Maeglin Lomion, son of Eöl and Aredhel, cursed seed of the Kinslaying.
Disclaimer: I certainly do not own Maeglin, Aredhel, Eöl, Nan Elmoth, Anguirel, Gondolin, or whatever else's mentioned in that story, I'll see as it goes along… Bow to the Great Master Tolkien. Bow and worship.
By Le Chat Noir
The darkness softly shunned the trembling rays of the breaking sun, a sun still young. The weary clouds, growing slightly pink under the caress of pale light, lazily stretched in the clearing sky, slowly settling down as sheep in a meadow in the draft of day. The blades of green grass danced in the light spring breeze, as the sunrays began to peer shyly over the mountains, and a fresh scent of flowers rose in the air. Songbirds awoke from their songbird-dreams and quietly, almost going unnoticed so natural they were, sang their songbird-songs rousing the laughter of rivers.
But in the dark Nan Elmoth, none of this was known.
So it was not the first rays of sunlight that roused the child from his sleep that morning. In fact, in the perpetual shadows in which the Stardusk Valley drowned, one could not have even guessed that it was morning. As he turned over in his bed, blinking the confused dreams –what had it been about already? A white building, reaching for the sky…- away, his mind hazily wondered what exactly had woken him. He stretched himself, enjoying the bed's coziness and warmth, and stared at the ceiling. Tried to remember. Today was a special day…
Startling, he sprung out of bed, and started dressing in a rather precipitate way.
Father had gone on one of his long journeys yesterday evening. He remembered now him taking him in his strong arms to kiss him good-bye; a rather rough kiss, he had found. But the fact was there: today, Father wouldn't be home. And Mother had promised.
Half opening the door as carefully as he could so as not to make it creak, he peered out in the corridor. Deserted. Closing the wooden door behind him he ventured with light and silent footing out of his room, and made his way like a shadow unheard and barely seen through the intricate mazes of the House of Eöl.
But he knew his way. It had been countless times he had snuck along those walls, in dark mornings when everyone slept still.
The door opened with the slightest push, offering no resistance to his small strength. As usual on these days, she was sitting near the window, the only window, and was gazing into the black forest, northwards, always. Pride was in her stance, even as she sat, for tall and fair was she even among her own people.
Upon hearing his coming, she turned her gaze to him, and it was bright with unshed tears, though a small smile played on her lips.
"Mother, you promised."
The little boy climbed onto his mother's lap, and she passed a loving hand through his still short hair.
"Which one would you wish to hear?"
"The building of Gondolin."
He raised his glance to her expectantly, eager and hungry to hear once more the story he knew already by heart. Aredhel sighed; but in her heart she could not deny that she was glad that her son found interest in the doing of the Noldor, and maybe hoped, somewhere, somehow, that those hours spent to tell him of her kind would one day bear their fruits. She gently kissed his small forehead.
"'Tis a lengthy story than that of the building of the white Gondolin, and every stone, every gem and even the singing water drops that fill its fountains have each a story of their own, in the city that was built in remembrance of Tirion. But if the true telling of Turgon's hidden city begins a very, very long time ago, in another age, and of that age we will speak not, for our time is short. However, years and years ago, when this tale begins and unfolds, Turgon still reigned over the realm of Nevrast from the tall tower of Vinyamar that watched the sea, and the faithful Finrod had his throne in the fortress of Tol Sirion…"
And so time passed, and years went by, and spring arose, and winter fell, but in darkness Nan Elmoth dwelt and shadow veil shrouded her days…
The child grew within the night. When he reached the age of twelve, his father gave him a name: Maeglin, Sharp Glance, for he saw that his son's eyes were sharper than most, and could see things forbidden to common gazes. In her heart, Aredhel thought that it wasn't a wonder, as for all his life Eöl had confined him under the dark foliage, never seeing other light than the blazing fires in his father's house; but she spoke her mind not. And in her heart she had given him a name since he was born, in the forbidden tongue of the Exiled, and that name was Lomion, the Son of Twilight.
Eöl familiarized him with the art of smithery, and he proved to be a good student, eventually spending most his time in his father's forges. He also taught him the common Sindarin, and the mysterious Avarin, known to none but the Avari themselves, and in secret Aredhel gave him lessons of the ancient Quenya. Soon he had become fluent in all three languages, and his head was full of the ancient lore his mother had poured into him when he was a child, with vivid stories and songs. And, day after day, as he became more and more skilled as a smith and grew in body and mind, also grew in his heart another longing, another yearning he could not quite place, but just the want of something else, that made his mind wander and his gaze turn to the north, where his other kin roamed, where there was another life was perhaps waiting for him. 
His spare time he spent with his mother, or alone in his chamber to read; but there were few books in the House of Eöl, and he knew them all by heart.
And so one day Eöl waited for him in the forges in vain. Angry, like a father be to his young and favorite son who refuses to come down to dinner one day out of caprice, he climbed the stairs to Maeglin's room, and threw the door open without warning.
"Why did you not come to the forge?"
But the young elf paid no heed. Standing at the window with his elbows on the sill, he gazed at the darkness outside with an eerie smile on his lips, a strange gleam reflected in his eyes as if it was light he saw instead of shadows. For a moment, Eöl stood baffled, as never before had Maeglin looked more like his Aredhel.
"Father, I wish to ride North tomorrow, with Mother, in search of her kinsmen."
Instantly, Eöl stiffened, froze, and his gaze turned to ice, but the youth, who looked like he was trying to pierce the darkness and see beyond, in his imagination, paid no heed.
"You shall not. I… have need of you in the forge." His voice had fallen to an icy growl, though still he tried to hold the bewilderment and slowly rising wrath. However, he was caught completely off-guard, and found the words hard to come by, ashe had always hated talking.
Maeglin turned to face him, and his face fell with incomprehension, and a shadow of doubt. He had always known. He must have known; at least, guessed, somehow. He wasn't stupid. No. He was all but stupid.
"Then, next week? Next month?" Why continue fooling yourself? Never. It was never. But just, just dwell a little more in the sweet illusion…
"No. You… will stay here."
The young elf's eyes opened wide, and suddenly in his heart there was a fire sprang up, and for the first time, he looked at his father and saw him through. He saw that Eöl had always intended for him to remain in the darkness by his side, a prisoner like his mother, never to see the light he craved. He saw that Eöl wanted him a slave to his smithery, caught between the boundaries of the forest, shunning the sunrays like himself. He saw that Eöl wanted him Maeglin of Nan Elmoth, noble among the Teleri, and a hater of his kin.
"You have no right…"
The Dark Elf advanced on him.
"I have every right. I am your father. You are Maeglin, son of the House of Eöl, and in the House of Eöl you will remain!"
He was systematically cut off.
"Your mother has no kin."
And now he was towering above the not yet fully grown youngster, tall and powerful, but Maeglin's fury grew only greater for he knew he could not win.
"My Mother is Aredhel, Daughter of Fingolfin, she is Ar-Feiniel, the White Lady of the Gondolithrim! My Mother is the King's sister, she belongs…"
Abruptly, his fingers came to close around Maeglin's thin forearm with crushing strength. The younger elf felt the tears coming to his eyes, but did his best to hold them back, not wanting, refusing to break down in front of him.
"Your mother is my wife."
His voice had dropped to a whisper spat through clenched teeth. Unconsciously, Maeglin imitated him. Their eyes stared into one another's, unblinking, hateful, both gazes burning with new-found dislike and wrath.
"You took her by force."
"And how would you know that?"
He felt his father's iron grip around his arm, and felt quite sure that it was broken. During all those years, he had almost forgotten his father's incredible strength, and could not refrain a bitter tear to roll down his cheek.
"She told me. She told me all." He knew what a dangerous position he was putting Aredhel in, but at the moment couldn't care less. "She told me how you lured her into your hole by your dark magic, how you captured her and forbid her to go, how you forced her into your bed!" And he shouted it into Eöl's face. "She is no wife to you! You got no consent from either her family, or her! You have no rights…" 
But he was stopped short again, as Eöl threw him with all his might towards the far end of the room, and he ended crumbled in a heap at the foot of the wall. He stirred no more, and his body was only moved by his regular, sharp breathing. Eöl looked at him, and sneered.
"You should know your mother better, for all the time you spend with her. You should know that was it not for her consent, you would never have been born."
And then he was out of the room. Slowly, Maeglin sat up, leaning his back against the wall, and began painfully massaging his arm, to make sure that the bone wasn't fractured.
1- Aredhel never actually revealed to Maeglin the emplacement of Gondolin; so that place would either just be Himlad, or Maeglin is bright and guessed because Aredhel was always looking in that direction.
2- Actually, it is said that Aredhel wasn't taken entirely by force, but I guess that would just be Maeglin's point of view. Eöl's point of view is rather different, as one can see, but I guess none of them detain the actual truth.
Eöl's character was difficult to interpret. I will hold to my belief that he is an Avari came West, despite the obvious fact and statement that he is in fact a Teleri. But I've read on Ardalambion that the name might be an Avarin name, and therefore it just got stuck in my big stubborn head that Eöl be an Avari… In my opinion, he loves his wife and son fairly well, however not in the best of possible ways. I mean, I do not think that Maeglin is constantly beaten by his father or anything, just that he has always been a little scared of him, which is not a wonder, knowing Eöl's ways… But I guess they were on quite friendly terms, like master and student, before Maeglin submitted him his… request… Note to self: never, ever bother Eöl…
I've decided not to post long chapters for this, so they could be a little faster in coming…