It's a good thing they're creatures of the night, then. 

Maybe the causation goes the other way- but it still works.

"I think you'd be staying up and sleeping in late no matter what."

"Is that what your deductions have told you?"

"It's been hinted at, here and there."

"Hm. Clever."

"We are."

"I'll not argue."

Giggle. "And wise, too."

"You flatter me."

"That, or I'm just honest, or I'm teasing you. Or all of those at the same time."

"You're getting trickier."

"Your bad influence, surely."

"You don't find value in it?"

"Now, who says I don't find value in being bad?"

"You'd be using a different definition of the word than most."

"Hm, I think many people would call sneaking and spying, gambling and whoring pretty damn bad..."

"Not in this part of town."

"We're a bad lot."

"The dregs of the barrel."

"The last ones left when the barrel's drained, at any rate."

"Indeed."

Broad grin. 

And: details of how they'll build up their empire? 

Lots of those.

A lot goes into keeping the wheels moving in the right direction.