As the anon mostly responsible for coming up with the details of Finn, I can say that he was designed to be the anti-version of Marco and his harem. IIRC>Finn=Marco>Huntres Wizard = Connie>Marceline = Anne>Flame Princess = Luz>Princess Bubblegum = Tulip
Parts of their story was that they were hunting Marco for the bounty put on his head by Star, as well as to have an actual fight between adventurers good and evil. Alongside that, their main base was St. Olga's for the princesses. And with that Finn would kidnap princesses and reform them to be part of his personal army and slaves. There's probably more I'm missing, but I wrote one of my best stories with Finn trailing Marco and his harem through a busy, inter-dimensional, immigration crowd.