During the Alessian Slave Rebellion, it is said that Pelinal Whitestrake screamed out Reman's name in a battle, millennia before he was born. It has been claimed that Alessia's spirit appeared to King Hrol and his men, as they fought to keep the Empire together. And from this meeting "King Hrol did love unto a hillock" and conceived Reman with the spirit of Alessia. That hill, later named Sancre Tor, was where the babe Reman Cyrodiil was found, with the Amulet of Kings.
He was brought up in court and accomplished many great deeds in his youth. He led the fight against a major Colovian revolt at the age of 12, and when he was 13, had every Colovian King bowing to him.
Eventually, he rallied Colovia and Nibenay against the Akaviri Invasion and is responsible for the construction of many Skyrim forts that still dot the landscape even in the 4th Era. He accepted their surrender, and reunited Cyrodiil, Skyrim, and High Rock once again. Having to deal with their problems, he immediately set to taking on the issue of the issues between High Rock and Skyrim regarding the Reach. He split the Reach in half, cutting down on the Reachman's abilities to control mines and support military efforts. But not all of Reman's problems could be solved with a military mind.
The Thrassian Plague ripped through the land, but in the mayhem of it, he would move into Valenwood and the Summerset Isles, pacifying militant ideas in many Elven people amidst the Camoran Dynasty.
He was never named Emperor and died of unknown causes. When he died, his Amulet of Kings was passed to his son and his son would become the first Emperor.