In contrast to most other characters, Lewis has a very refined, posh way of speaking. This, in addition to his very neat attire (including a bowler hat) and accent, makes him appear to be fairly well-to-do. He sometimes makes mention of a cousin, though doesn't go into any more detail.
Lewis can be often seen playing Liar's Dice in Escalera, as well as Casa Madrugada and Thieves' Landing. His skill in gambling, as he would admit, is not anything to boast about. The player can also sometimes find Lewis lazing around the Manzanita PostGeneral Store. Depending on Marston's honor, the player can have two encounters with him; with high honor, he will, despite saying he is a man of small means, track him down and pay some money in return for saving his friend's life. With low honor, he will say that Marston killed his cousin and will challenge him to a duel, hoping to bring justice and vengeance.
You're the man who intervened, saving my friend from terrible distress and hurt. Please, let me offer you a gift in thanks.
—Lewis Eddins, offering Marston a gift
I am a man of small means, but please, take your pick from my selection of goods.
Lewis appears to travel a lot as he can be found in Escalera and Manzanita Post which are on the complete opposite sides of the map. He will also track down the player to either reward you or challenge you to a duel depending on the players Honor.