Summary: They said he did it for Camelot, Gwen said he did it for her, but Merlin knew that Lancelot sacrificed himself for him. Merlin/Lancelot implied Gwen/Arthur.
The first time they had spent the night together they just slept, comforted by the presence of the person beside them.
The second time, it was to remind themselves that they were still alive. It was after Morgana's invasion, after they took back Camelot and Gwen and Arthur were somewhere together. So, Merlin went to the only person besides Gaius who knew about him and his magic, the only one he could trust.
Lancelot had looked as lost as Merlin felt and when Merlin had kissed him in desperation to feel something besides fear and loss Lancelot had let him, had returned the kiss just as desperately. They had spent that night together on Merlin's small bed, the first of many, Lancelot's weight there to ground Merlin, reminding him that someone was there for him just as Merlin's heartbeat under Lancelot's ear reminded him that they were alive.
It became habit over the years, though Merlin spent more time in Lancelot's room than Lancelot did in his. None of the other knights knew, or if they did they said nothing to them, each other, or Arthur.
As time went by Merlin let go of his crush on Arthur, something he had known would never come to anything and let himself fall in love with Lancelot.
Lancelot who would ask to see Merlin's magic and then make love to him while his eyes still glowed gold. Lancelot who wore his blue neckerchief, hidden well, into the tournaments he participated in. Lancelot who knew all of his secrets and failures and still loved him, still touched him with kindness instead of fear, who looked awed every time Merlin cast a spell when they were in privet and would look for him when they were on patrol and they were attacked. Lancelot who would cast a quick grin in his direction when something lucky happened while they were fighting.
Lancelot who accepted that Arthur was his Destiny and that Merlin had to protect him no matter what.
When the Dorocha happened while Merlin was protecting Arthur it was Lancelot who began to take him back to Gaius, Lancelot who sat by him, prepared to spend the whole night awake to protect him, keep him safe.
It was Lancelot who he had shown the Great Dragon, who had looked at Merlin even more amazed than usual.
And it was Lancelot who looked at Merlin, so determined to sacrifice himself to keep Arthur safe and alive. Lancelot had known that Merlin and him being together would come second to protecting Arthur, he had accepted that before Merlin had kissed him that night so desperately.
Lancelot looked at Merlin and he wondered about himself, doubted if he really was the noblest of all the people in Camelot, perhaps he was so among the knights but how could he possibly be more noble than Merlin. Merlin who time and time again save the life of both Arthur and his Father, never asking for reward or praise, who followed Arthur into more danger than Arthur had a right to put him in.
Lancelot followed behind Merlin and wondered what it was about his lover that made him so perfect.
It was Lancelot who couldn't let Merlin die, couldn't live in a world without Merlin, couldn't bear the thought of following Arthur knowing that the king was the reason his love would be gone from him. Lancelot who would not live without Merlin in the world, somewhere breathing the crisp air, fighting Mythical Magical Monsters by Arthur's side.
So, while Merlin talked to the Cailleach, Lancelot walked around them to the torn Veil between worlds. Lancelot looked back only once, any more and he knew he wouldn't be able to go through with it. He looked at Merlin's horrified face and smiled, just a little, before he spread his arms out to the edges of the Veil and stepped through the tear in the world, carrying Merlin's face behind his eyes, Merlin's voice echoing in his ears…and then there was nothing.
Merlin watched Gwen cry, keeping his tears from over flowing, only moments ago he would have sworn that he had no more tears left in him to cry but it seemed that he was wrong.
When Arthur left Merlin followed, there was no body, this was for the people of Camelot to honor the fallen knight, Lancelot had ceased to exist as they understood the moment he stepped through the tear, and Merlin could still see the smile that had been Lancelot's last gift to him, cried in the bed they had shared because somehow it still smelled like him and when he was forced to return to his tiny bed he took Lancelot's spare cloak and wrapped himself in it as tightly as he could, breathed the scent of the fabric in and pretended that it was Lancelot's arms that surrounded him.
It was days later, it could have been weeks Merlin's perception of time had become worse than usual, when Merlin felt his grief fade enough that it no longer felt as if he were in a waking dream(nightmare, because if Lancelot was dead than what else could it possibly be.)
He heard it in the lower town while he was handing out potions for Gaius. The Villagers whispered that the bravest and noblest of the knights sacrificed himself for Camelot, so that it would always stand. He heard Gwen whisper to Arthur later that day that Lancelot had sacrificed himself for her, to fulfill a promise, a promise to protect Arthur, bring him home to her.
But Merlin knew, he knew what Lancelot had really sacrificed himself for, and it wasn't Camelot, it wasn't a promise to Gwen, and it wasn't to protect Arthur, it was for Merlin, and Merlin knew why too.
Merlin lay on his bed, Lancelot's cloak wrapped tightly around him as he sobbed as silently as he could, so as not to disturb Gaius and tried to find some comfort in the knowledge that the reason Lancelot had sacrificed himself was so Merlin would live, because Lancelot had loved him until the moment he died. But the knowledge of this was a cold comfort because Merlin really just wanted Lancelot's warm arms holding him close as he whispered that he loved him into his hair when he though Merlin was asleep, when Merlin just wanted to feel his lips against his palm when they couldn't quite get away with a proper kiss.
Knowing why Lancelot was gone would never give him comfort, not when he couldn't get rid of the knowledge that Lancelot's last act was to smile at him so that his smile was the last image of the man he loved that Merlin would ever have, knowing that was the closest to comfort as Merlin would get, because it was the last bit of comfort that Lancelot had given him.
So… umm… a little depressing but I really wanted to write something heartbreakingly emotional about Lancelot's sacrifice, sorry if I made you cry but I hope you liked it a little.