My population just went from 4. to 134. How? Well. I reclaimed a fort that had greater fire imps(those things in Fortress Defense, might be wrong name), who were apparently already reclaiming it. After reclaiming it, and killing some of the imps, I retired it. I unretired it, went to others in the unit list to see if there were any imps. weren't any, so I went to citizen, and discovered 130 fire imps on my side. Now I have a mayor. Considering that I had 4 dwarves, and dwarvish civs were dead, this is good. Haven't tested to make sure they'll do jobs.
Hm. Interesting - Did you succumb to invasion when greater fire imps were sieging it?
Could be interesting way to get troll or ogre citizens - get them to siege you, succumb, reclaim, retire, unretire. Ogres may be short-lived (20-30 old age) slow learners, but they're over twice as large as elephant man.
Did your civilization remain the same? Do imps and dwarves have different groups of allegiance?
They didn't siege my fort. It wasn't my fort. I retired a different fort, went to legends, noticed that fire imps had recently reclaimed a fort, went to fort mode, noticed I could reclaim the same fort, Fought some of the imps, retired, unretired, and suddenly I had a lot of fire imps.
I didn't check the civ, but I'm fairly certain all of us are in the dwarven civ, which by the way, was dead. I haven't checked the imps, but I'm fairly certain they have allegiance with us. Guess I should check their info to see what it says. Interesting though, huh?