Suggestion for Episode 4, C-Plot: On his way to Estolad (maybe afterwards depending on how we want to be with timing/location), Sauron encounters Boldog, fresh off of the Gelion-Ascar Stockade battle. They have some terse words over the idea to send a battalion or so of Orcs to kill Men. Sauron wheedles Boldog into admitting that Gothmog ordered the assault, expresses annoyance at Gothmog's blunt instrument mentality. He then reaches the outskirts of Estolad, takes the form of an Elf, coerces a Hadorian into leaving with them, and kills them (gender is irrelevant, could be either). By the time he infiltrates the Council as Amlach, there's an indication that he's been doing this for a few more times, pinning them on the Green Elves.