How does Deep Wound work?

If it takes off 20% of your maximum health, does that equate to 100 damage at 500 health? Or does it decrease proportionally? e.g. 125/500 -> 100/400

Your current health and your max health both decrease by 20% of your original max health.
For example if you were on 400/500 hp BEFORE the deep wound, you will go down to 300/400.

However the effect only pops in the next time you take dmg. This is why eviscerate followed by executioners strike is one of the best one man spikes in the game.

That and the ever popular one two three combo of sever artery, gash and final thrust. Same principle. Tag on bleeding, deep wound and then huge damage on the final thrust because they will be below 50% by that time.

So the answer is no, it would go from 125/500 to 25/400. That's why Eviscerate is the gotta-have skill...it's the damage from the hit, usually in the 100 range, plus a 100 points of 'virtual' damage from deep wound. Note that the health loss from deep wound caps out at 100- if you happen to have 125/2200, a deep wound will only take you to 25/2100.

ooh, you learn something new every day

Also the hidden factor that makes it even sweeter: 20% reduce healing

Cut that monks healing by 1/5th while he is trying to save a target. So far only infuse is enough but being a large heal even hurts the team more.

More importantly its like said before its how deep wound applies that it kills. When you hit your evisc you deal 100+ dmg. Deep wound is not applied on the target. ExStrike 100+ dmg and deep wound applies cuting your current and max health. Its a 300+ dmg spike that reduces the healing on the target.