I gather that in some circles, even wondering what and how monsters eat, breathe, eliminate, and reproduce is considered extremely foolish. Even uncreative - if you can't let go and just say a dungeon is a magic place, you're missing out on something critical. You're letting the hobgoblins of foolish consistency devour the joy of dungeoneering. It's just a stupid game and you're doing it wrong.
I don't agree.
To me, the answers to these questions:
- act as prompt to creativity
- provide hooks for the players, in the forms of weaknesses and clever ways of beating/using the monsters.
When you know what a monster eats, breathes, how it reproduces or originates, you have a more developed and more interesting monster. And generally, you end up answering them anyway. A non-answer is still an answer.
Even "these guys are formed from darkness and are fed on our fears of the underground" is an answer.
The answers you end up can get very interesting.
For example: If you decide that orcs, in fact, sprung from darkness in the depths in response to the fears of the surface dwellers, then what? Does that mean they thin out if the population does so, for lack of psychic sustenance? Or does familiarity with the surface area breed comfort with it and contempt of its dangers, and thus civilizations drive out the fear-eating orcs?
Same with breathing. Do they need air? If so, they need ventilation, and PCs walling off their lair with walls of stone and suffocating them is a valid tactic. If not, they can live in dark, airless corners without regard to ventilation. This affects where it makes sense to stock them.
Do they breed true, with orc kids and orc women? Or do they propagate magically - and if so, under what circumstances? If they're made, can the PCs (or certain NPCs) make them on purpose? Can this propagation be interrupted in some way? Is there a monster generation pit somewhere down on level 3 pumping out orcs? If so, who is running it?
And so on.
Even boring, old, tried-and-true "they eat normal food" means you should have stockrooms full of supplies, figure out what fellow monsters they eat or who and what they trade with for food. Orcs taking slaves to trade out for food makes sense in a way it doesn't for fear-of-darkness created orcs.
This kind of "monster ecology" doesn't need to be grounded in modern science (although it could, if that makes it cooler). But answering a few simple questions like that creates a much richer and potentially more fun experience. Even if the answer is, it's a game magic food pixies drop the food off, you've got an answer. It tells you something about your world.
I think the idea that monsters don't need to eat to live can be seen as a cop-out by some players, which will yank them out of their suspension of disbelief faster than you can say "You open the door and find a 10' x 10' room containing six giants!" You may end up explaining how the dungeon is a magical place, and by the way so are these other monsters, and how medieval folks wouldn't ask that kind of question, and so on. Throwing those players to the curb and calling them foolish is equally unhelpful. Instead, revel in their questions, and have answers that make the game more interesting.
Next up: What Do the Monsters Eat?