Grimrock

i have tried to backstab in almost every Battle i fought and didn't land i yet. The mobs are just too fast to get to their back. Someone give me a Hint how to do it...my Rogue is rather useless atm and i'm considering to use 2 Mages instead.

there are two ways:
1. Try it on a snail or skeleton. They're slow enough that you can sometimes get behind them before they can turn.
2. Sneak. Hide around a corner and wait till a monsters back is turned, then charge in and strike.

I found the best way to use backstab is to lvl ice magic - normal freeze let you hit once and improved long enough for 2-3 hits. That freeze is the best even without backstabing, haven't found any strong side of any other school of magic.

As floorbelow said, you can quickly go behind a mob and slash him before he turns (keyboard required though) but it only works on slow mobs, so forget it when facing a spider for example.

All in all this makes a Rogue rather useless doesn't it? Ok, its Reach abillity is nice put replacing it with a second mage upped my DPS massively. Meh =(

Maybe you're right, but I think it's a matter of choice. IMO rogue is more versatile and I personnaly prefer versatile characters.

I sincerely hope there isn't any "no magic" zone in the game or you'll be in big trouble with 2 mages

wouldn't the level 19 air spell "Invisibility" help

yes, invisibility plus backstabbing is a great combo

Invisibility or Frostbolt freeze effect work good with a backstabbing rogue.

I prefer rogues to "specialise" in ranged weapons lately (volley with a nice bow is nice), although backstabbing + bonuses can be nice too.