(Disclaimer: I own neither Kingdom Hearts nor Naruto. Or "The Minstrel Boy." It's free-domain and was written by the long-since-dead Thomas Moore.
Why are Deidara and Demyx hanging out together? That, dear readers, is a story for another day. We'll see when I get to it. Also, I'm really bad at writing people singing, so bear with me as I practice that some more.)

Two blonde artists were keeping each other company, more or less left to their own devices as most everyone else was out on missions. The two of them got along quite well, though it helped that their personalities were so similar. Even though one of them preferred to avoid fighting and the other was as big an arson as Axel. So far they had spent the morning lounging about the living room, listening to the musician's music and making small talk when they weren't settled in a comfortable half-silence brought about by the music.

But after a while, one of them decided it was time to break the silence and ask about something that had been bugging him for a while.

"Demyx," Deidara, who was currently sprawling over the back of the sofa across from said Nocturne, began, "I have a question."

"Hmm?" Demyx barely turned his attention away from his sitar to answer.

"I've been wondering something for a while. You're a brilliant musician, that much is obvious from how much I've heard you play," the ninja ran a finger along the edge of one handmouth as he spoke, "but have you ever played any traditional songs?"

Demyx looked up from his sitar at that, but didn't stop playing. "Sometimes, but not very often. No one around here really cares about traditional songs," the next few notes held a sad tone to them, "Which is unfortunate, 'cause I prefer them most the time." Mostly, though he didn't say it, because the tune and pace of traditional songs was so very flexible.

"Well, why don't you play one for me?" Deidara questioned, "I wouldn't mind hearing one."

"Do you have anything in mind?"

"Not really. Just... play whatever you know."

At that, Demyx actually paused his flowing song and looked at the Stone ninja. After a time he smiled and turned back to the sitar, playing an aimless tune as he decided on the song. All at once the melody turned towards somber and Demyx began to sing, his voice rising and falling in time with the music.

"The minstrel boy to the war is gone, in the ranks of death you will find him; His father's sword he hath girded on," the Nocturne's voice was soft, though still loud enough to be heard over the music, "And his wild harp slung behind him."

Then all at once his voice soared, the music swelling with it. "'Land of Song!'" Demyx sang as the minstrel, "cried the warrior bard, 'Tho' all the world betrays thee, one sword, at least, thy rights shall guard,'" the song his fingers plucked out dipped towards the quiet side again, as did his voice, "'One faithful harp shall praise thee.'"

This was followed by a lengthy bout of nothing but music- the flowing, living sort that was the Nocturne's specialty. Quiet and somber, as such a song demanded of course. But it was still recognizably Demyx's music. After a time, he began to sing again.

"The Minstrel fell, but the foeman's chains could not bring that proud soul under; The harp he lov'd ne'er spoke again, for he tore its chords asunder;"

Once again the sitar music swelled with his voice, "And said 'No chains shall sully thee, thy soul of love and brav'ry!'" Demyx sang, his voice strong and clear, "'Thy songs were made for the pure and free- They shall never sound in slavery!'" the music became somber again as the end of the song neared.

Deidara had almost begun to give an enthusiastic applause before he realized that Demyx wasn't finished yet. The Nocturne's music could be describe and nothing but sad, his voice quiet as he began to sing again.

"The Minstrel Boy will return we pray, when we hear the news we all will cheer it. The Minstrel Boy will return one day, torn perhaps in body, not in spirit." Demyx gave a small shake of his head to accompany the line.

"Then may he play on his harp in peace," all at once, the music took a turn towards melancholy, "In a world such as heaven intended. For all the bitterness of man must cease, and ev'ry battle must be ended."

Only then did Demyx's music fade away into nothing as his song reached its close.

The silence that followed was an utterly stunned one. In fact, Deidara almost fell off the back of the sofa. Which would serve him right, really. You were suppose to sit on sofas, not sprawl over their backs. It looked like some of Xigbar's habits were starting to rub off on him. It was quite a while before Deidara felt like he could say something half-way coherent without stumbling over either his own tongue or the lump in his throat.

"That," he finally choked out, "was absolutely amazing, Dem."

He could have sworn that the Nobody blushed as he started strumming a random melody on his sitar. "Thanks."

"Where did you learn that song? I don't think I've ever heard anything like it before."

"I heard it on one of my missions a few years back," Demyx explained, "Once the mission was finished, I stuck around long enough to learn it."

"Have to say, I'm damn glad you did. I don't think I've ever heard anyone play nearly as well as you."

That coaxed a grin out of Demyx. This was one of the reasons- aside from both of them being artists in their own right- him and Deidara got along so well; the arsonist always appreciated his music when he played. "So," the musician looked back at his sitar, "Have anymore requests?"

"Actually, yeah. Ever heard 'The Devil Went Down to Georgia?'"

With out any warning, Demyx suddenly burst into song. "Devil, just come on back if you ever wanna try again- I've told you once, you son of a bitch, I'm the best there's ever been!"

If anyone else had been within the vicinity of the living room, they could have heard the uproarious laughter of two blonde artists that weren't thought particularly highly of by anyone but themselves.

But you know, they didn't really mind.