The Torn Banner artifact can be found in Thang Talath, in the central part of Sea of Núrnen.
Torn Banner, Third Age, circa 2940
Ungol have set upon and partially consumed this crimson banner representing the Dark Lord Sauron. This is not merely a symbolic act; the oversized children of Shelob are organizing against the Uruks, forming raiding parties to bring down what they consider to be invaders into their lands. Whatever truce may have existed between the factions has now ended.
"Damn. They got the whole raiding party. And et the flag.
See the webs? It's Spiders. Filthy creatures. Likely coming up from the valley down south.
We should clear it out.
You should shut your big yap. Don't nobody come back from that place.
Wonder if they're working for Shelob? Sauron used to feed her, and I guess she don't remember whose pet she is. It might be time for a reminder."