Avatara's explanation is short & sweet, and to the point. Here's my wall of text.
The biggest pair I have problems with are the flies and spiders, as it's usually early in the game and I don't have the resources to build two different lairs.
Remember that you can't have creatures who hate one another in the same lair. Those creatures are
Flies & Spiders
Bile Demons & Skeletons
Warlocks & Vampires
Demon Spawn & Hell Hounds
Dark Mistresses & Samurai
This also means you don't want those creatures even walking through the other's lair. So some intelligent design for your dungeon is in order. Don't make lairs "throughfares" that all creatures have to travel through to reach, say, a hatchery, treasure room, or whatever. Try to keep lairs needing only one entrance and away from your main concourses. By mid-game always plan to have two lairs, seperate from one another. Force creatures to live there by dropping them into them.
Sometimes you can't help this due to restraints on your designs, and even if you design well, conflict is often inevitable. Depends on the creature's demeanor. The Horned Reaper is the most notorious troublemaker, then, to a lesser degree, you have vampires, then warlocks. Those are really the problem three.
Creatures get unhappy for various reasons, but the big ones are not getting fed, not getting paid, and being picked up too often. Late in one game ( I'd already conquered it) I pissed off all my trolls by dismantling all the workshops, heh. Many creatures get unhappy just because they're bored.
Reapers I never allow to mix with the general population - I always build a seperate (and locked!) area for them, consisting of (minimum) a lair, training room, treasury, and hatchery. Once they're trained to 10th level I convert the training room to one of these two: a temple or a guardpost. Either one will often keep Horny busy and thus happy.
Vampires are almost as bad, they're very temperamental. Warlocks are less so, but they're ambitious and vain, and in large numbers they'll rebel. I almost always have one 1st level warlock being tortured on the rack by mid-game. It teaches the other's a lesson and makes them work (study or train) harder. Also, by this time I want vampires, so I grab a high level wizard, put him in a scavenger room, then start "sacrificing" 1st level warlocks that appear by dropping them in the graveyard and then slapping them to death. If you keep warlock numbers low they'll behave.
Problem vampires I either bribe, or torture if they just won't get happy. Sometimes dropping them on a Temple tile (not *in* it!) will help their attitude, but often not.
I also pay more "attention" to these creatures. If they gain a level I give them a lil' extra gold as a reward. Whenever I "visit" the Horned Reaper I give him a taste (one) of gold to show I'm pleased with him ( I often hand-feed him also, believe it not- and keep all my fingers!). I don't slap the Reaper (never!) and never slap the vampires, either. Warlocks I slap around a good deal, to teach them who's the boss. Still, if the level, or if there's a bit of gold lying around, I reward these guys fairly often, and it keeps them happy.
Spiders and flies, skeletons and bile demons, etc - it really depends on whether I want the creature or not. Both flies and spiders are weak creatures, so I usually just let 'em fight it out, the fittest will survive. Skeletons and BD's I both like, so I seperate them.
If a creature just won't "get happy", put them on the rack for the Dark Mistresses to enjoy.
Post edited June 08, 2011 by SlackerSupreme