Right, but I supply them with food, hehehe... That castle is connected to the city by the sewers (that castle is on the outskirts). One of the monsters discovered that entrance, so it began feeding with people (is a half-fiend one). That was not long ago.
The castle, being in the outskirts, hadn't got that problem before (food), some monsters attacked the near villages, but that villages soon went away from the area (when they discovered form where the attacks were). Now the nearer farm is miles away so the monsters used the entrance to the sewers and began eating only corpses... when they became more and more insatiable, they began attacking people, at first only beggars, so people didn't care. But beggars also began to be scarce, then the hunt switched to people in general... among them a rich merchant and a noble's son. So the city's guards (now occupied in other subjects I have in the city) hired some trustworthy mercenaries (my PC's, hehe) to invstigate, so there they are.
But I'm talking about need-to-feed monsters hehehe. Mydemons are chained up in an antimagic circle or the like,

BTW, putting some of them in some form of extasis is a good idea, just to give a surprise with the trigger

Other "experiments" are just undead (well, BoVD undead, they are "funnier") or other simply dead, to make a "nice" background (in their own cages, trying desesperatly to get out, bitting their bars...)
And so on...
Hey, you people are just giving me lots of ideas!

Thank you all!
Bye!
