Scimitars can also be used to backstab.
And yes, it is a
very useful attack.
A multiplier is used to calculate damage from a backstab, so damage will be x2, x3, x4 etc. depending on the level of your thief.
An especially good way to use this skill is to backstab an enemy mage - you can often kill them outright before they start to cast.
Another tip is you should always be prepared to run after your attack if facing more than one enemy or if your first attack is unlikely to kill outright - anything which will make you move faster is useful (boots of speed, potions, haste spells etc.)
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Time is an illusion. Lunchtime doubly so.
Epona of The Laughing Hyenas and The Ladies Guild.