Traldor's Lvl 8 ability

[Skeletoria]

" Reduces enemy target's resistances versus all magic damage by 5%. Only resists gained from items are reduced."

Does it do this when i hit enemy for first time or something? Cause it doesnt say " When item is used" Like the debuff charge on moon hammer..

Tnx in advance

 

[Vodkafairy]

its a passive ability, so its always up. you just hit 21% resist instead of 26% for example