[ssw22]

Having any of the 7 attacktype modifiers that deal direct damage on a weapon will cause it to do damage.
However, having more than one modifier will make the weapon deal damage according to whatever resistance is lowest on the target.

Say you are attacking an ice fiend with a Bow of the Messiah (Attacktypes: Physical, Confusion, Cold)
The ice fiend has 99% armor and
50% cold resistance.

For each attack, only the cold attacktype will deal damage because the resistance against it is lower than the other attacktypes.

Any attacktype that does not deal direct damage will stack with the current damage dealing attacktype.