The first dwarf was a moody dwarf that went mad, and I tried to keep it away from the others with a burrows (it wasn't successful, as expected: maddwarves don't care about restrictions). I later reused the same burrows (with redefined boundaries) to contain a vampire that I finally managed to kill off. I nicknamed the vampire "Vampire Scum", if you've got a method for locating the data about the dead. The burrows is called Vampire Cell.