OK, researching some lore I came up with a couple of good prospects. I really want this to be very lore friendly, so here’s what I’ve found. Basically after the White-Gold Concordat was signed:
Spoiler “Hammerfell, however, refused to accept the White-Gold Concordat, being unwilling to concede defeat and the loss of so much of their territory. Titus II was forced to officially renounce Hammerfell as an Imperial province in order to preserve the hard-won peace treaty. The Redguards, understandably, looked on this as a betrayal. In this, the Thalmor certainly achieved one of their long-term goals by sowing lasting bitterness between Hammerfell and the Empire.” And “In the end, the heroic Redguards fought the Aldmeri Dominion to a standstill, although the war lasted for five more years and left southern Hammerfell devastated. The Redguards say that this proves that the White-Gold Concordat was unnecessary, and that if Titus II had kept his nerve, the Aldmeri could have been truly defeated by the combined forces of Hammerfell and the rest of the Empire. The truth of that assertion can, of course, never be known. But the Redguards should not forget the great sacrifice of Imperial blood - http://www.uesp.net/wiki/Skyrim:Breton, Nord, and Cyrodilic - at the Battle of the Red Ring that weakened the Dominion enough to allow the eventual Second Treaty of Stros M'kai in http://www.uesp.net/wiki/Lore:Fourth_Era#4E_180 and the withdrawal of Aldmeri forces from Hammerfell.”
So I could add into my backstory for Valerius that after he escaped from prison, he and his men escaped to Hammerfell and joined the Redguard in their war with the Thalmor. After the Treaty of Stros M'kai, Valerius and his men once again went underground, but by this time they had acquired a few Redguard allies who joined in their covert operations. It seems to me that Redguards would be the obvious choice of ally for anyone wanting to form an underground resistance to the Thalmor.
Now, looking through Redguard history, I found this:
Spoiler “Hunding (one of their great ancestors) devised a plan of seven battles leading the Armies of Hira further and further into the wilderness to the foot of Hattu, where the final battle could be fought. Hunding called his plan the "Hammer and the Anvil". With each battle Hunding's Singers would further learn his strategies and tactics, grow strong in the use of the Shehai, and be ready to defeat their opponents in the seventh battle. And thus it was, the six first battles were waged, each neither victory or defeat, each leading to the next. The larger armies of Hira following the small army of Hunding. Outnumbered thirty to one, the singers never faltered from the Way. The stage was set, Hira and his Army maneuvered to the base of Hattu Mountain, where the hammer blow was delivered. The battle was pitched, and many singers fell that day. Hunding knew, that the singers who lived would be few, but Hira and his empire of evil would not live and so it went. At the end Hunding and less that twenty thousand Singers survived the day, but no army of evil was left to pillage and murder, more than three hundred thousand fell that day on Hattu. Of those who were left to run and live, all were scattered to the four winds, and organized force no more.”
So, the base of Hattu Mountain was where they made their final stand against their enemy. This was their “point of no return” so to speak. It was either death or victory at this point. It was their Alamo. So, this underground resistance is essentially the last hope for the people of Tamriel to defeat the Thalmor just like Hattu was their last stand. So, what about “The Keepers of Hattu” as the name for my faction?
Others I thought about are “Remnant of Ansei” http://elderscrolls.wikia.com/wiki/Ansei , although that one seems a little too Redguard specific. And I also thought about “The Keepers of The Shehai” http://elderscrolls.wikia.com/wiki/Frandar_Hunding
I will most definitely have a unique Shehai weapon as a reward, and at least a little backstory on the craft.
