A/N: Written after watching just the first two episodes of the show.
Arthur sat in his room in the castle of Camelot. It seemed eerily quiet after the evenings revelry and the later fighting that had broken out. Kay sat with him, a protective arm around his slumped shoulders. Merlin was somewhere in the castle, no doubt busily plotting and manipulating people. At the moment, Arthur couldn't bring himself to care about Merlin, or England, or visions of the future, or fate. He stared at the drying blood on his hands as they lay loosely in his lap. Most of that blood was his father's. His real father, the one who raised him, not the one who'd used Merlin's magic to deceive and rape another man's wife and father a bastard—the one who'd died protecting him, not the one whose death had destroyed his life. The dark red stains on his hands blurred. He felt tears slipping down his face once more and he leaned into Kay's side, finding some comfort in the familiar warmth of his brother's embrace. "Kay, I'm so sorry."
"No." Kay's response was quick. "No, this wasn't your fault. Don't try to apologize to me." Kay sighed and tightened his arm around Arthur. "You've done a lot of things you could apologize for, Arthur; but this wasn't one of them—you can't apologize for being born."
"But Kay, I wasn't born your brother—if Merlin hadn't chosen your family—"
"Arthur, stop. I do not and will never regret having you as my brother." Kay shook his head with a soft laugh. "My amazing, arrogant, wonderful, irritating little brother."
Arthur turned his face too look into his brother's eyes. "I can't lose you, too," he began, terrified. "I-I won't let them take you from me. You-you have to promise me that no matter what happens, you won't get yourself killed for me, Kay."
Kay grasped Arthur's hand in his and gave it a firm squeeze, shaking his head with a sad smile. "You must know I can't make a promise like that, Arthur."
Arthur shook his head violently. He felt as though tiny shards of ice were piercing the skin all over his whole body. "No, Kay, no. If I lost you...I couldn't bear it. I couldn't—"
Kay gave Arthur's hand another squeeze. "You'd have to, Arthur. You'd have to. If there's one thing I've learned about you recently, it's that you can do the impossible when you have to."
The brothers sat in silence for some moments before Kay broke it once more. "Do you remember when we were little and you used to crawl in bed with mom and dad when you had a nightmare or were scared by a thunderstorm?"
Arthur gave him a halfhearted elbow in the ribs. "I remember you used to do the same thing."
"Yeah, but when I decided I was too old to do that anymore, you decided you were too old too, even though we both knew you were younger than me. And then the next time you had a nightmare, you were sitting in your bed, trying so hard to cry quietly, but too proud to go back on your word. Your pathetic whimpering woke me, and I took pity on you."
Arthur grinned, remembering. "You told me you'd had a nightmare and asked me if you could sleep in my bed." He shook his head. "I knew you were lying, but I didn't care." He paused, in thought. "You were always a better brother than I deserved."
"And finally you admit it." He favoured his brother with a mocking smile that did not reach his eyes. "You need to sleep."
"My big brother, always taking care of me." He began to lie back against his pillows, then froze. "You'll stay?" His wide eyes looked so scared and childish, like a little boy who'd woken from a nightmare only to find he still could not escape it.
"Of course," Kay replied, lying on his side beside his brother. The bed wasn't really big enough for two grown men, but it didn't matter. He'd do the impossible for one night; Arthur needed him to.