This is Urist McImdsm of Iton Datan, member of the Tomb of Heroes.
We've been attacked by (initially) 32 undead. They've since eaten chickens and badgers.
We are holed up in our fortress, which has walls on three sides with a 1 tile water moat outside of the walls, and a river on the right of the fortress. We are 22 dwarves strong, safe inside our tunnels, with ample food and drink. The drawbridge is up and secure.
We don't really have a functioning military, but I suppose we now have the time to train.
What options do I have for getting rid of these undead attackers?
I was thinking, we could build an archery platform and when they walk near, pelt them with bolts, but then, can't undead only be killed by decapitation? How should we handle this?
Our beards grow long whilst we ponder the situation.
Best Answer
By the looks of it, your fortress isn't in an evil region and therefore you aren't dealing with evil weather undead, but regular undead, which are susceptible to all forms of damage (piercing, slashing, crushing) - archers will take care of them just fine, provided there isn't a necromancer to reanimate the bodies. Traps remain the safest option to deal with most foes, but are rather boring. Slashing traps and weapons, however, are far from boring if a necromancer is around, turning one zombie into a bunch of individual zombie bits. If you're certain there isn't a necromancer around, you can just take them in melee combat or do any number of things to them (hell, make a zoo out of them) except killing them with magma (but you can make an undead magma zoo). If there is a necromancer, I would suggest annihilating them with drawbridges or containing them with cage traps, to make sure they can't be raised again. You can also use cage traps to catch a necromancer (drawbridge annihilation isn't easy to do if the enemy is hidden, which necromancers are, initially), but keep in mind that they will raise dead even from inside a cage.
If they breach your fort and you don't believe you have the strength to defeat them in combat, walling yourself off and preparing may be a good solution. You can use burrows to get your dwarves all in the same place. If they happen to occupy an important part of your fortress, you can get them to move by chaining an animal in a long tunnel/maze and giving them a path to it, then walling them inside.