Power weapons are a variety of close combat weapons that easily cut through any armor.
The most common forms of power weapons are a modified sword with an internal power supply, an activation mechanism and often a monofilament blade. Making it cut trough most infantry armour without the power field even turned on.
What truly gives the power weapon its armour rending capabilities is the power field.
A complex mechanism, only the most transendant of mechanicus operatives know how it works.
The power fields practical effect is that it rapidly disintegrates everything it touches and only the deamonic and rare protective fields give any protection against it.
Only the richest of people can afford one, and only very succesful individuals are awarded with power weapons.
Example power weapons are: Power sword, Power axe, Power fist and the Ohmnissiahn power blade.