Is there something I can use to set an event trigger when my enemy is down to 5% health?

Also looking for a mod with a 'Killing Blow' text that you really can see.

I sound violent... o.O Anyways, I've tried stuff like PowerAuras (both for sound and visual), Scrolling Combat Text and some other mod i can't remember, but it all turned out to be pretty anti-climatic or just not working.

If you have no luck finding an existing addon then you may have to write one yourself.... not too hard. You just need to register for an event (Killing Blow) then play a media file (sound). Maybe 2 lines or less or Lua. You should be able to find some small addon that is close and maybe modify it to your liking? I know it's not exactly what you were asking for but I have had to write many addons for my own benfit because there are none out there that fot my needs exactly. Only takes a little bit of patience to learn, even if you have no previous programming experience.

I appreciate the answer :)

I found something called PvPSounds and KillingBlow, I'll try em out and customize them to my own liking if needed.

Thanks!