Each one can be separated down into several categories, and each needs to be dealt with differently. Arachnid There are two types of arachnids that you will face in Thief 2. The first is rather small, and difficult to hit yet easy to kill, while the second is quite large and takes a few hits to kill. You will not see many but they do tend to prove an annoyance.
Arachnids are easiest to deal with from a distance with broadhead arrows.
There are several varieties of humanoids. You can expect to encounter Servants, Civilians, Guards, Thieves, Mechanists, ape beasts, tree beasts, and Hammers. Humanoids will comprise the majority of enemies that you will encounter, so know how to defeat them well, as you will have to on a regular basis. Most humanoids are highly susceptible to a blackjack strike on the back of the head. The only unfortunate thing is that this does not work on tree beasts, ape beasts, or all guards.