'Vampires' (z-V) and 'Werebeasts' (z-W) are unique threats that can infiltrate your fortress. Vampires are immortal, charismatic, and drink blood, often posing as regular dwarves. Werebeasts transform during the full moon, becoming incredibly powerful and attacking indiscriminately. Both can cause immense chaos if not dealt with swiftly.

Strategy:
- Vampires: Look for dwarves who don't eat/drink, have no family, or have suspiciously high skills. Isolate suspects in a 'Prison' (b-r-p) or 'Cage' (b-j-c) and interrogate them. Execution is often the only way to remove them.
- Werebeasts: Identify infected dwarves by their transformation. During the full moon, lock down your fortress and isolate the infected. Werebeasts are vulnerable to silver weapons. Once transformed, they are hostile to everyone.
- Prevention: Be wary of new migrants, especially those with no known history.