Honestly, it had all started out as a joke.
They had been classical musicians in a town that wanted Rock. Being such, they rarely if ever got any gigs. Technically, all of them could have made good money as Chunin if they ever decided to unretire, but music was their calling and they were determined to follow that calling to the bitter end if need be. They'd started following people around and playing music they thought fit them both as a joke and in order to keep their skills sharp.
Then, that Uchiha kid they'd followed for two days had hired them...
"What's this Obito?" Namikaze Minato, Future Yondaime Hokage of Konoha asked pointing at the near orchestra sized group of individuals who had followed the young Uchiha to that day's training.
"It's my band." Obito replied with a grin. "I give them half my pay, and they follow me around and play awesome music for me."
"Yeah, okay, whatever." Kakashi said, eying the group that were currently tuning their instruments and running through the scales dubiously.
Eventually, Team Minato got used to being followed around by an orchestra and started to damn near forget that they were there even despite the music.
The people who encountered the team however...
"Where the hell is that music coming from?" an Iwa nin who was fighting a pair of Konoha brats who were trying to retrieve their teammate asked as dramatic music that oddly enough matched the situation almost perfectly sprang up seemingly out of nowhere.
"Uh, Ishi, don't look now but we're surrounded by an orchestra." another Iwa nin said to his companion who was fighting a certain Uchiha with a newly awakened Sharingan.
When Obito had seemingly died an hour later, the mournful dirge that had been composed on the spot brought tears to the eyes of all who heard it including the Iwa nin who had been guarding the mission objective before its destruction as it was played the entire way back to Konoha.
13 Years Later:
Naruto frowned slightly at the sign sitting in front of the group of homeless people that said "Will play for food". While he would like to have someone new to play with, the Old Man had warned him several times that he shouldn't play with old people no matter how many times they offered. The people in front of him weren't old old but...
"So, what kind of games do you play?" he asked.
The next morning:
Kakashi groaned and buried his face in his hands when he saw who had followed Naruto to training that day. If Naruto hadn't looked so much like Minato and the timing weren't completely off, he'd almost be willing to swear that the boy was Obito and Kushina's son. The brat seemed to be an almost perfect combination of the both of them.
"Why did you bring a bunch of smelly homeless people to our team training?" Sakura asked, too stunned by the sight of the bunch of ragged looking people who were tuning worn instruments to start yelling like she usually did when Naruto "Did something stupid".
"They're my band Dattebayo!" Naruto exclaimed. "And, they're not homeless since they live in my apartment now."
As Sasuke watched the ragged and worn looking orchestra play for Naruto, he found himself wanting a band of his own. Not a classical one like these buffoons however. Maybe that punk band that had gotten kicked out of that bar he'd been passing by would be amenable to playing for him...
Three and a half years after that:
Out on the battlefield:
As the tension between the two Uchiha and the joined ninja army increased, the dramatic music that was playing in the background rose towards a climax.
"What is that...? Hey! You stole my orchestra!" Tobi yelled from his perch atop the Jyuubi.
"I stole nothing from you-ttebayo!" Naruto yelled back. "If you didn't abandon them in the street..."
With the resurrected Hokages:
"Is that some sort of Uchiha thing?" Minato asked as he watched a group of musicians that were covered in piercings and tattoos set up and start doing sound checks.
"Is what some sort of Uchiha thing?" Tobirama asked as the musicians he'd been trying to ignore as they brought up memories he'd been trying to repress did their final sound checks.
Suffice to say that when Hashirama started telling the story of his past and his secret history with Madara, he had to yell to be heard above the drums, guitars, and screeching musician...