Trigger that makes less damage from an item

[jedchrizt]

How do I make a trigger that makes it so that I can reduce damage done to the target by a certain amount?
In example: 10 Resistance would equal to about 1% less damage from all sources.
How can I make it so that I can put it on an item (item abilities is full with other item abilities)from triggers?

 

[Just_Spectating]

would resistance be like armor?

 

[jedchrizt]

would resistance be like armor?

Something like it.
The 'Resistant Skin' is the perfect example.

This is a little difficult to elaborate but I'll try my best.

My Edit Item Ability list is full of other abilities (armor/ap bonuses) and I want to know if there's a way to add another ability to the same item via triggers or what not.

 

[Just_Spectating]

add a spell book to your item(up to 12 more passive abilities), but disable it in triggers initialization.

 

[jedchrizt]

add a spell book to your item(up to 12 more passive abilities), but disable it in triggers initialization.

Ah, thank you.