The Revolutionaries are a rebel group split from the UOGE. They left either as the result of disagreeing with the UOGE or the surrender and subsequent re-assimilation of the former Rebel armies back into their original groups. They were unable to find a suitable location to attack or gather the forces to do so until John Cain J-217 arrived. Knowing of their existence, when 217 went AWOL, he took command of the poorly organized force. Once ready, he used his knowledge as a Void Walker to attack Nirn. He used his inherent public speaking skills to try, unsuccessfully, to persuade Tamriel's people against the UOGE. It is possible for the Dragonborn to side with the Revolutionaries during the Battle for Nirn, but he will end up becoming an underground resistance fighter. The Revolutionaries destroyed the continent of Thrass during their early attack because of the resistance from the native sloads. They cloaked the continent of Akiviri with adavnced stealth systems. This forced the UOGE to have to fight a bloody battle later, which ended in the covert Silencerz( not a typo, their name is spelled with a z), allies to, but not members of, the UOGE, setting off fissure charges which blew half of the continent into the sea. This base explained why the destruction of Revolutionary HQ's in Hammerfell, Skyrim, and the Aldmeri Dominion seemed to leave them unphased.
Though the Revolutionaries put up a decent fight during the Battle for Nirn, afterwards their power shifted towards asymmetric warfare. In Tamriel, they launched guerilla attacks and rarely engaged in open combat, such as at the Siege of Winterhold, where they erected a massive defensive dome of the city while trying, unsuccessfullly, to break the ward being generated to protect the College there. The only other major engagements were the Battle in Akiviri and the Battle of the Tropics.