Faultline recruited Newter and Gregor the Snail after saving them from being arrested by a hero. After they met her conditions. This 'founding' was roughly three years before the story started.
The group pulled a job on the North American Tinkerblack market and infiltrated a high-security asylum seeking information on the Dragonslayers. After defeating a team from the BostonProtectorate, they recruited Labyrinth, an inmate who had been recently transferred there.
The group were among the forces that arrayed against the resurgent Slaughterhouse Nine-Thousand to try to stop Jack from bringing about End of the World. The extent and form of this aid is unknown and was ineffective in preventing the event regardless.
↑Tattletale nodded, "Faultline's crew does anything short of murder. You can say her personality sucks, you can say her powers suck, but I'll admit she's very good at finding hidden strengths in the people that work for her. See those two guys? When it came to powers, they got a bad roll of the dice. Became freaks that couldn't hope to pass in normal society, wound up homeless or living in the sewers. There's a story behind it, but they became a team, she made them effective, and they've only messed up one or two jobs so far."
"Gotcha," I said, "Impressive."
"Keep in mind, though, we haven't screwed up any. We're 100%."
"They've done something like three times as many jobs as us," Regent pointed out. - Hive 5.1
↑ 4.04.1"Just saying my group won't be getting directly involved in this without a reason," Faultline spoke, "We won't be going after the ABB unless they get in my way or someone pays my rates. It's the only workable policy when you're a cape for hire. And just so we're clear, if it's the ABB paying, my team's going to be on the other side of things." - Hive 5.1
↑The nature of Faultline’s meeting with her ‘crew’ is essentially what happened in canon. - Snippets: Before Worm
↑"Uh, yeah," Brian looked a touch embarrassed, he rubbed the back of his neck, "It didn't go well. We tried with Spitfire, and she got scared off before we even got to the job offer. Our fault, for bringing Rachel along that time."
"And then she got recruited by someone else," Alec added.
"Yeah," Brian shrugged, "She got snagged by Faultline before we got a second chance. - Insinuation 2.6
We'd just lost our last major advantage in determining how this could play out. Jack was getting everything. He was a wiki-walk away from getting details on everyone who was arrayed against his new Slaughterhouse Nine. - Excerpt from Sting 26.6
↑The conversation continued. Egg had a hard time listening, as emotions stirred.
They were traitors. All of them. Faultline had stolen good capes away at the end of the world, working on infrastructure and backend, gambling they’d be ahead if everyone made it through Gold Morning. She had only been part of the final fight because she’d been forced to be. Gregor and Newter and those others had been the same, because she called the shots.
He didn’t blame them so much as he blamed her. She called the shots, she owned the shots. A team only worked if everyone was on the same wavelength, willing to follow the leader. - Excerpt from Interlude 19.a II