item ability for a chance to block any attack?

[steelknight999]

I had this shield attachment but I want the item to have an ability to block an attack by chance.I saw something like this in dota(Poor man's shield).

 

[Kino]

Hardened Skin.

Really, a lot of these questions you ask are very basic object editor knowledge.
I suggest you tinker around with the editor for abit, so you don't have rely on outside help for the most basic things.

 

[steelknight999]

Is there a way for the damage reduction to be a percentage?

 

[Kino]

Is there a way for the damage reduction to be a percentage?

Use a Damage Detection System, script the whole damn thing.