They travel together, and learn about each other.
She's got a good shot, but he's better. He looks good in hats, but she prefers a bandanna. She hates fighting humans, but is good at rad-scorpions and the like. He can't stand robots, but takes out feral ghouls like no other. She prefers stealth and can snipe like the pros, he prefers to barge in and kill outright.
They've got a lot in common.
They can't stand the asses in Tenpenny Towers, but would love to live there. They don't like traveling in the open at night. They both like her dog, Dogmeat, but don't want to take him along on missions. They both ignore the rads they get and eat whatever the hell they want, and they both think the radio is annoying as hell when Three Dog shouts.
They didn't talk much.
It was agreed upon that he would have the extra storage room in her house for his own, and that he was welcome to come and go in town as long as he was around when she need him. Due to his nature, he didn't stray from her often.
"Let's reclaim the mall." She said one day, as they were both sitting in her living room. Wadsworth, her robotic butler was cleaning up from their dinner, Dogmeat was sleeping in the corner, Charon was cleaning and repairing his favorite weapon (a combat shotgun) and Anastasia had been reading up on history in a book she'd found in one of the mall's museums. "We could make it semi-safe again. Even start a new settlement or something!"
Charon sat silent.
"We could do this! We've taken on whole hordes of these people!"
More silence.
"When?"
"Tomorrow we can leave and make our ways through the subways. I've got ties at GNR, so we could stay the night there, then be in the mall by the next day and start taking people out."
He looked down at his shotgun.
"Whatever you wish."
"I wish you would tell me what you think."
"…"
"Charon?"
"We'll leave in the morning."
And no more was said about the ordeal.