help with Imperil.

Hi, hi.

I like to be a Bard, and I was trying to beat Omega 6* but I had no luck, I always run out of time. Was thinking on use Imperil since a lot of people say it's very good.

But I don't know if my Imperil is working.

Every time I use it says "miss" but I don't know what am I doing wrong. Does Imperil has a high chance of not connect, am I positioning wrong or it does not affect all kind of enemies?