Thieves are probably the trickiest class to get started on, due to the variety of skills they have to start out. Thieves are oriented towards being damage dealers and they excel at hiding in the shadows. They also learn some spells (shared with mages and healers) but due to the thiefs nature, they can only be cast on the thief himself and not shared. The thief trainer can teach you some new spells once in a while.
Thieves can use any weapon, but the best weapons, in general, are those that are easily concealed. This would mean you want a dagger, shortsword, or even a longsword. Halberds, greatswords, and other large weapons carry large penalties to your ability to hide. They can backstab enemies to do massive damage, as well as leaving damage over time spells on their enemies. When they cast spells, they use their hp instead of mp.
Thieves passively do more damage and can trigger deadly combos while hidden.
When the thief levels up, it will gain some hp. Every few levels, it will also gain a bonus to hiding in the shadows.
throw- you can
throwany item at a target. Some weapons return when you throw them, making them excellent candidates for ranged combat.
hide- this is what gets you going. Hiding will allow you to hide near any wall or tree to move around unnoticed by the world. Beware, just because you’re hidden doesn’t mean that nothing can see you - depending on how far away you are, and how skilled of a thief you are, your ability to hide varies!
reveal- if you do this, you’ll come out of hiding. You don’t generally need to do this, as stepping into a non-hide area will already do it, but sometimes it’s useful to do.
steal- just as you’d expect, you can steal from creatures. This means that you can steal their gold, or even their items!
backstab- learned at skill 3, backstab will be your bread and butter. Anything that you would have the element of surprise on while hidden is a target (the element of surprise means that they can’t see you). You’ll charge towards your target and do massive damage if you hit.
mug- learned at skill 7, mug is just like you’d expect. It’s a combination of
steal, where you run to a target, hit it to do some damage, and also steal from it. You need an open hand and a one handed weapon to do it.