Oblivion - Mehrunes Razor

I found Mehrunes Razor in Oblivion.  This weapon is described as "Daedric banishing on strike".  Is it supposed to be one-hit-kills?  I've used it on several enemies, and while it is a good weapon, it's far from one-hit-kills.  Am I supposed to do something to the weapon?  Are there only certain enemies it works on? Thanks.