From what I've gathered, we're used as 'experiments'-- that's all of us, not just some, sadly-- some are kidnapped, other times, it's... everyone who has an experiment placed on them. One working for the Malnosso told everyone that we're to work for them, fighting for them. They placed information on this in the back of everyone's journal. Some are sent on 'missions.' I don't know what they are, I've not been on one myself.