Board Thread:Suggestions forum/@comment-33157907-20180604110423

Of course, not all NPCs.

Haradric Archers and Mordor Orc Archers as well as Black Uruk Archers are most likely to use these, and about one in five should use poisoned arrows. Their drops should also be poisoned arrows.

Next, the Gundabad Uruks, Angmar Orcs, and Dol Guldur Orcs. About one in ten should use poisoned arrows.

Finally, the Rhudel Archers and Gundabad Orcs. One in fifteen should use poisoned arrows.

Of course, this should be nerfed, so the poison effect lasts three seconds only, and Utumno Orcs don't use poisoned arrows. 