Post by bornhj
will consume the charges/doses of Deadly Poison that you've got on your target, and use your combo points at the same time, and deal instant nature damage. So if you're got 5 combo points, and 5 doses of Deadly Poison stacked on that target, then your Envenom move will remove those 5 doses of Deadly Poison from the target and deal instant damage according to the "5 doses" line of the tooltip (for me, it's 1081 damage).
Importantly, if you've only got 3 doses on the target, and pop a 5 CP Envenom, it will use all
of your combo points but still only do the damage according to the number of charges on the target (in this case 3, or for me, 649). So it's generally a bad idea to use Envenom if you have more combo points than Deadly Poison charges up.
At the same time, if you use Envenom when you have 5 doses on the target, but only 3 combo points, you will do the 3 dose damage but leave 2 doses of Deadly Poison on the target
Also important (and the thing that makes Envenom viable) is that it deals instant nature
damage, not physical damage. This means it isn't affected by armor mitigation. However, that also means that the damage can be wholly resisted ("Your Envenom was resisted by Gamon."), still using your combo points and consuming your doses but doing 0 damage. Bear this in mind. :)