A/N:
I don't own any of the characters in this fic, nor do I own Supernatural.
This could be read with Cas and Balthazar together, or just as brothers. Lemme know what you think!

"Dance with me, Cassie."
"Now is not the time for such frivolities, Balthazar. There is a war waging, and I need your help."
"Yes, yes," Balthazar waved his hand dismissively. "Lighten up a little, or your face will be stuck like that forever."

Cas' ever-present frown deepened as he studied his brother. Of course his face – well, his vessel's face – was stuck like this; humans weren't shape shifters. He realised belatedly that his brother had used a human figure of speech. For an angel who had such a low opinion of humans, he certainly embraced their way of life, indulging in ménages, whatever they were, alcohol and, apparently, dancing.

The younger angel moved a little closer as the strains of violin music suddenly broke the silence. At once, Balthazar offered his hand to him, and, to his surprise, he took it. Indulge his brother, and perhaps he would hand over the weapons more easily. He didn't see Balthazar's request as anything more than stalling for time, trying to find an excuse not to hand the weapons over. He wouldn't ever realise that his brother actually wanted him to relax and forget about the war for a little while, that his care actually went that deep.

Balthazar wanted to take the weight off Cas' shoulders, even if only for a minute. He wanted to see Cas smile again, feel his joy like he had when they'd been in Heaven and had been infinitely closer than now. Of course he missed those days, but it would do no good to dwell on it and how different things were now, how much closer Cas was to that Winchester monkey. Subconsciously, his expression darkened, but cleared quickly, almost guiltily, as Cas spoke.

"I can't dance, Balthazar," he informed his brother gravely, as the music drifted into something much more upbeat.

"Just relax, Cassie. Let me lead," Balthazar smiled, the crow's feet at the corners of his eyes deepening. He guided Cas' hand to his waist, shifted their linked hands and then rested his other on his younger brother's shoulder. His vessel was relaxed, whereas Cas was just as stiff and uncertain as always.

"I said, relax," Balthazar smiled, looking more than a little amused. He pulled Cas close, so that their chests were touching, before pulling him around the room in time to the music. As he'd expected, Cas shuffled along with him, looking perplexed and unsure of himself. He was far from graceful, though his shoulders had relaxed a little.

Balthazar couldn't help but chuckle in amusement as he spun Cas, much to his younger brother's confusion.

"Here," he murmured softly, pulling Cas close again. He moved much more slowly now, showing Cas simple steps to a quick step dance he'd seen performed long ago. It took two demonstrations and some patience before Cas mastered it, however messily. Clearly his vessel wasn't built to be graceful, and definitely not to dance. Yet Balthazar knew that Cas, his true form, was one of the most graceful things he'd ever had the pleasure to lay eyes on. Really, humans had nothing on angels.

Again, Balthazar tugged him close, exerting a little will to start the song again.

"A quoi ca sert, l'amour..."

This time, he led his little brother around the room with much more success, and he could feel his vessel relaxing under his hands. At the edge of his consciousness, he could feel a curious sort of joy, which was reflected on Cas' face. They moved together in a harmony reserved for those who knew each other inside and out, which, Balthazar mused, they did. They'd learned to fly together, had gone to war together, and now danced together. Of course they knew each other well.

The song reached its crescendo, at which point Balthazar twirled Cas again, smiling broadly as his coat swirled around his knees. Cas was a quick study; always had been.

Laughing, Balthazar shut off the music with a flick of will. He pulled Cas close, enveloping him in a tight embrace and nuzzling his dark hair. Oh, it was nothing like their true forms embracing, was nowhere near as comforting and fulfilling, but he would make do for now.

"All lightheartedness aside, Cassie, promise me you'll be careful," he rumbled, cheek pressed to the top of his brother's head. "You will come back for me when all this is done?"

"Yes, Balthazar, I promise. How is it you put it?" Cas paused, tilting his head a little as he tried to remember Balthazar's exact words. "'You'll always have little old me'."