Virtually nothing is known of Roger's early life, though it's suspected that he may have been orphaned at some point. It is known that in his teens, he became a con artist, and would later train others in the art. It was in 890 that he officially organized the "Con Brigade," which is commonly believed to be named after Connor and Brigid, as a sort of pun. The scams the group pulled often involved convincing people they had authentic relics that had once belonged to The Land's first two people, and selling them at exorbitant prices.
While the Con Brigade was not what anyone would really call a gang, per se, their work became known, as they traveled to other villages to pull their scams. When Capp of Kimrin was seeking out gangs in other villages to unite with his, in 899, the first person he met was Cherilyn Amalgamator, of Triscot, who had long been impressed by stories of the Con Brigade, including at least one con they'd pulled in her own village. And so, Roger was one of two people she suggested to Capp that they should join with (the other being Don of Plist). Roger wasn't at all sure he wanted to become a gangster, but his partners in crime thought it sounded both fun and lucrative, and an interesting change of pace. And so, he allowed the other three gang leaders to teach him just how to go about leading a gang. However, the very nature of gangs was changing rapidly, becoming something fundamentally different than they had ever been before. As it turned out, Roger already had many of the necessary skills, and even taught the others a few things. And so, Capp, Cherilyn, Don, and Roger, became known as "the Big Four," the original founders of LandOrder (which would later expand to other villages).
In 904, when the surname law was passed, Roger chose the name "Fourth," as he was considered the fourth most important person in LandOrder (even if technically he was equal to Cherilyn and Don). At least, that's what most people believe is the reason. It might be more accurate to say it was simply because he was the fourth of the original four to join, even if in retrospect it's common to think of the Big Four as having created LandOrder simultaneously.
As might be expected, Roger is an excellent liar. Some people have said that that makes him the perfect person to run the branch of the gang in First Village, which is the seat of the World Council. (Because, of course, it's popular to think of politicians as liars, whether seriously or in jest.) But more importantly, his skills at ingratiating himself were considered useful in dealing with certain politicians who secretly had ties to LandOrder. Most notable among these, as it would much later be revealed, was Demos Royal himself. Of course, in spite of the mutually beneficial arrangements between Demos and LandOrder (as well as their rival, InterGang), no one in the gang really liked Demos. Capp himself usually refused to deal with Demos directly; relegating the task to Roger was a luxury he allowed himself, as capo. This is something which Roger long resented, as he didn't like Demos any more than anyone else, though he did realize that it made sense both because of his powers of persuasion and because of location. But it was often clear to his own employees as well as to other LandOrder gangsters from other branches that he held a grudge against the other three members of the Big Four, the reason for this grudge apparently wasn't known to the three of them (at least until 912). In spite of this grudge, he was always loyal to Capp and used his skills at social pleasantry to pretend to get along with the other dons, at least on a professional basis.