They probably met at the Outworld marketplace. Ferra was homeless, an orphan, struggling to survive. She tried to steal some stuff, was chased and got caught, but in prison she found Torr. He used to be a good guy, but was treated poorly, like Ferra, and was kept there for some crime and might've been tortured and intoxicated with some mind-altering drug. Ferra, after a while, thanks to her small size, found a way to escape and freed Torr. They fell in love and protect each other.