Lit only by scattered torches, The dungeon lies far underneath the castle.  Bandits and Thieves who find themselves there are met with cold stone walls and floors, with chains and bars restricting movement.  Guards patrol the corridors, keeping an eye out for any escape attempt or misdeed.  The only comforts afforded in the Dungeon are the piles of hay for sleeping.
Dungeon, Inside Castle
criminal
cockroach
I am a cockroach. People find me disgusting and dirty, but they do not know how hard my life is. I fly from village to village looking for a clan of cockroaches to join. Together, we cockroaches plan to take over the kingdom once our army is big enough.
Ha - you wouldn't be the first human to try it.  The guards keep a pet swamp wyrm down there.  They like to watch it eat over enthusiastic prisoners. Pff! Why would I listen to a nasty cockroach! I eat your family for breakfast.. You... you eat *cockroches*.  You MONSTER!  And here I was going to offer you a chance of a lifetime! What's the use.. I'm chained up.. But if you are a nice cockroach, you could get me that wooden stake. My last dungeon mate carved it before he.. He's just not here anymore.  Hmp!  Well I don't know.  You hurt my feeling most excruciatingly. I'm sorry. I just got ahead of myself. I'm just angry. I'm not even supposed to be here, I never hurt anyone! If you want to get to that stake, you'll have to crawl on this chain. Phah, you can't even tell a spider from a cockroach. We have different eyes and everything!  Give me that, you'll just try and turn it into a web... Ah, so I have mistaken you for that spider over there. It must be the endless nights of agony! Well... I suppose you only have two arms, so life must be difficult for you.  Listen, I can help you out, but there's a catch to it. And what is that? How would you like to join... the Cockroach Coalition for the Fair Treatment of all insects.  We're a fair minded group, and you can bet if we were in charge, we'd not put an innocent man like you in jail. You are quite the humorous, but kind cockroach. You have yourself a deal.