Ravos Ashvale is a private moneylender operating in the shadow economy of Fallcrest — the kind of figure who does not appear in official records but whose name most people in the lower city know. He handles transactions that banks will not touch, collects debts that courts cannot easily enforce, and employs people who can go places his own operation cannot reach. He is not a villain in the theatrical sense. He is a businessman with flexible ethics and a clear-eyed understanding of what the Fallcrest underworld actually runs on.
In session 1, the job was simple: find Mikos Adelberry, a halfling trader who had borrowed money from Ravos and disappeared into the Sorrowmire without paying it back. Bring back the debt or bring back something of equivalent value. The party accepted, gathered their gear, and walked into a cursed swamp.
What happened in the Sorrowmire — the will-o’-wisps, the guardian, the mud, the donkey, the general chaos of a first session where nobody quite knows what they are doing yet — turned the party from a collection of individuals into something that worked together. Mikos complicated the outcome in the way that Mikos always did. The job technically got done, more or less.
Ravos never became a recurring villain. He was the man at the beginning of a very long chain: he hired a group of strangers for a debt collection job, and that group is now navigating the eighth layer of Hell. He probably does not know this. He probably would not care, as long as someone eventually settles the account.