40d:Demon

This article contains massive spoilers. If you do not wish to have your game experience spoiled, do not scroll down!

Here, demons appear as red and green ampersands.

A Demon is an evil fast moving creature that will either severely wound or kill your dwarves and animals. Their attacks include projectile fireballs and hand to hand combat. Most are living and as such are especially vulnerable to weapons with high critical boost such as spears and crossbow bolts.

Demons are immune to stone-fall traps, weapon traps, cage traps and will destroy your doors and floodgates. At least some of them are able to fly and survive under water and magma.

Defenses against Demons

The easiest way to deal with demons, of course, is the "dwarven atom smasher" - crushing demons under a drawbridge will completely destroy them (and anything else). However, this method is frequently seen as somewhat "cheap" and certainly by doing this you deny yourself one of the most fun encounters in Dwarf Fortress.

Demons, as large, living enemies, are somewhat susceptible to piercing damage - spear and arrows work well. A well trained, well equipped speardwarf can mix it up with frog and tentacle demons, however will likely not get the chance to close with a Spirit of Fire before being immolated by the Spirit's ranged fire attack. Spirits also lack most vital organs that spears target in any case. Spirits can be reliably brought down by marksdwarves, but expect losses on both sides of that matchup. You can signifigantly improve your survival rate by placing the marksdwaves behind fortifications - the incoming fireballs have a chance to not penetrate the fortifications, which is higher the farther away the demon fired from.

Finally, siege weapons can be useful against demons. A ballista bolt will kill a demon, and a ballista fired down a narrow hallway to channel the demons into your field of fire will kill several. Use walls and fortifications to give your siege crew some protection from fireballs, and prepare a backup plan as your crew will panic and run once the demons get too close, which will happen quickly as the demons are quite fast.

Frog demon: Arguably the easiest demon. Powerful combatant and can swim.

Tentacle Demon: Corrupt intentions.

Spirit of Fire: Arguably the hardest demon. Cannot swim, launches fireballs, is surrounded by fire, a powerful combatant, and can fly. Limbs sever when broken.