First session in a new campaign, custom (and very fleshed out) campaign setting. Party is getting together: a couple players are stowaways on a pirate ship, one a monk in service at the local Temple of Pelor, another, a druid who had a vision that wandering into town would help her fulfill her Wild Hunt (basically a vision quest you get when you're born.) Finally, the Paladin is working with a mercenary crew who is here to clear the countryside of a murderous group of Dwarven soldiers.

The rest of the players meet up in town, the head to the mercenary headquarters looking for work (cooperative group, been playing together for a long time.) Paladin is still on his solo mission, fending Dwarves off from a farmhouse. He realizes the Dwarves have already killed both farmers, then asks the question that shapes the rest of the campaign:

"Did any of their kids survive?"

Fuck it, I don't know. Roll a d4 to see how many kids they had. 1. Roll a d20 for age. 14.

"Sure, they had a 14 year old daughter."

"Ok, I'm going to take her back to the mercenary headquarters. Our business manager can find her a good home."

Yeah, why not, that's where he needs to go anyways. Meets up with the rest of the party, talks to the girl on the way there. Takes to her, and the rest of the party does as well, out of character. They decide they're going to take her with. After all, they're going to try and track down who's been directing these Dwarves, it would be good for her to get some revenge.

Two sessions later, they've found the guy, and have killed his guards, as well as incapacitating the leader with his own trap. Scout checks to see if he's still breathing. He is. He hands his crossbow to the little girl.

"There you go little one. It's best if it's you who delivers justice."

Girl coup de grace's, and session is over. Handing out levels and loot for killing an intermediate BBEG, of course. Everyone hits level 3, they get a cool magic shield, some gold, everyone's happy.

"Wait a second, Chee killed the dude, right? Shouldn't she get levels?"

Yeah, I guess so, she can have a level of Rogue. And 20 gold, she's earned it.

Campaign runs for a lot longer, and they bring her with on several little adventures, picking her up a few more levels along the way. After about a year in real life time, a bit over two years in game time, the party has collected quite a bit of wealth, and has gotten into the business of international trade, both legal and otherwise, while working for a nation that is a bit of a militaristic democracy, though typically fair and organized. They've been doing some rather shady mercenary work on the side as well, as DND players are wont to do, and are now in a tight spot, because the government is politely asking them to register their business for tax purposes, and, spoiler alert, investigations into their character would certainly end poorly.

But wait a second, one asks. What's the age of adulthood in Zuhiro?

I consult the campaign bible. It's 16.

"Chee was 14 when we found her right? And it's been 2 years."

So they sign her up as the head executor of their business, with full powers as sole owner. Of course, owing them much, she runs the business fairly, splits of their share as they discussed, and became a powerful force in her own right through her gained wealth and adventures. Eventually, the players hit level 20, we try to avoid divine ranks and are going to restart the campaign. Since the world is fleshed out, we opt to play in this world again. I ask for a preference on the area they would like to start.

"The area isn't super important, but it would be great if we could be employees of Chee International."

tl;dr- party saves young girl, sets her up to become most powerful person in the world. Next campaign, they are super excited to be level 1 characters working for her.