Part Two: In which Dawn fails to grow up.
Dawn never told Buffy she was leaving.
This was deliberate. When Dawn walked out, she took absolutely nothing with her from the apartment they had been sharing. She left the clothes Buffy had seen her wearing that morning in a crumpled heap on the floor, underwear inside jeans on top of shoes. She dropped her jewellery on the pile. She dropped a bowl of cereal on the floor just beside it, standing well clear so as not to get in the way of the splashing milk. It wouldn't fool a forensic investigation, she knew, but Buffy would never think to ask for one.
Dawn wore the clothes Faith had brought, picked out by the older girl - black and pink and a Hello Kitty T-shirt that drew a withering look from Dawn, and a slightly guilty grin from Faith. And then she followed the older girl out, shutting the door firmly behind her, and waited while Wesley performed the petty spell that would turn the key on the inside of the lock. And then the three of them walked down to the car, where Lilah was waiting for them, wearing a trenchcoat and fedora like a character from a gangster Film Noir and smirking like a triumphant succubus.
They told her afterwards that the only reason they approached her first was because they thought she was the most likely to take independent action.
It wasn't just the four of them, of course; Wesley and Lilah had put together quite the team. A handful of former Watchers, a couple of skilled enchanters, the various professionals who helped to train Faith. And Ethan, Ethan who supplied the magic, and much of the knowledge, and almost all of the… subtext.
Dawn liked being part of their little group. She was useful. She was appreciated. They worked her hard, translating texts, studying demons, collecting information. She'd never thought of herself as good with computers but, she discovered, that was mostly a result of comparison to Willow; compared to most of Wesley's team, she was a technological genius. Even so, she had to be careful; Ethan assured her that Willow would not be able to trace her magically, but he could do nothing about technology. Dawn never even checked her old E-mail account.
Buffy had always tried to keep her away from the action. Within a week of changing sides, Dawn had witnessed her first takedown.
They'd flown to Berlin, following reports of a sixteen-year-old skinhead girl who had killed two policeman with her bare hands during a Neo-Nazi demonstration. And Dawn had been encouraged by Wesley to help Ethan with his tracking spell, and had gone with Faith to find the girl, and had watched as Slayer fought Slayer and age, experience, and the brutal training regime imposed by Wesley won over youth and vitriol.
She helped load the battered, drugged, unconscious girl into the ambulance Wesley had somehow acquired, and didn't think at the time to ask what they were going to do with her. Later, when she questioned Wesley, he muttered something about 're-education', and started teaching her a new parry.
Dawn learned hand-to-hand combat, and basic sorcery, and ancient languages. She spent her time travelling from place to place, occasionally resting in their home base in Edinburgh, and she drew a salary for hunting rogue Slayers, the monsters that Buffy had created.
She never thought that Wesley might be using her.