Only distantly related to the famous House Marsin that figured so promptly in the early years of New Avalon, Raymond-Roger Marsin was born on the Outback world of June. Believing himself destined for something great, Marsin used his family's sizable industrial fortune as a springboard to success at NAMA and later with the AFFS. Becoming a company commander in the Remagen CrMM, Marsin waited in vain to see action during the FedCom Civil War, being among the part of the milita left behind well the rest traveled to the capital. His loyalty to House Davion weakened, partly due to bitterness at not taking part in what at the time promised to be the largest event of his military career and New Avalon's apparent indifference to Periphery pirate raids on the Outback which prompted the breakaway of the worlds which formed the Filtvelt Coalition and the Malagrotta Cooperative.
After receiving command of the Remagen militia in 3074 after the promotion of Jaime Francis to the Crucis March command staff, Marsin then proceeded to publicly and critically badger the AFFS High Command to deal with the piracy problem in response to neglect of the Outback. Responding to his criticism, Marsin was given overall command of several regional militia units and instantly set about staging operations against the pirate controlled Malagrotta Cooperative, repelling pirate raids before proceeding to forcibly retake the worlds of the Cooperative. Marsin's combat operations began with the defeat of a pirate incursion from the Cooperative on the 1st of September 3075, when the Remagen Crucis March Militia soundly defeated the pirates on the outback world of Baranda.
Earning considerable public praise for his successes and pro-Outback speeches, Marsin toned down his tirades against Yvonne Steiner-Davion and merely contained the worlds of the Filvelt Coalition. During the Camelot Summit held on New Avalon in October 3079 the Princess-Regent declared the formation of a new Periphery March, and on the 16th of October 3079 Raymond-Roger Marsin was made a Duke and declared to be Lord of the Periphery March. While the full extent of the honours granted to Marsin were unexpected, it was widely anticipated that the newly-minted Duke of June would not only finish the integration of the worlds of the former Malagrotta Cooperative but begin measures to bring the various worlds of the Filtvelt Coalition back into the fold.
- Masters and Minions: The StarCorps Dossiers, p. 39, "Raymond-Roger Marsin Profile"
- Jihad Hot Spots: 3076, p. 51 "Marsin, CrMM Defend Suns Again!"
- Jihad Hot Spots: Terra, p. 18, "Timeline of the Jihad"
- Jihad: Final Reckoning, p. 54, "The Jihad In Review"
- Jihad: Final Reckoning, p. 60, "The Jihad In Review"
- Jihad: Final Reckoning, p. 35, "New March, Dukedom For Marsin"