Revenge Question

[Kitteh]

I'm looking at a mf build (it's on the front page) and I have a question about the revenge skill.

Is it a 15% chance that it'll become available, and then you have to select it?
Or...
Is it a 15% chance that it'll just happen?

[Snerra]

15% chance that revenge will become availabe when struck (the button on the action bar will light up). You then have maybe 5 seconds (not absolutely sure) to activate it, which gives you time to get in range of several enemies for maximum effect.

[Kitteh]

Ah right ok, thanks

[Apocalypse]

its OP

more letters here