I'm a long term fan of Pendleton Ward's cartoon series Adventure Time. The show features Finn (a human 'fighter type') and Jake (a shapechanging dog) and is a show which makes many, many references to D&D, be it Liches or Bags of Holding. Pendleton has hinted that they are both paladins but the way Finn fights doesn't seem to fit with the Paladin's defender role.
I'd love to play a character like Finn; Finn goes for all out attacks and is rarely seen defending but he is portrayed as a righteous, do-gooder paladin. How can I make the paladin class fit a more offensive, freewheeling style like what I've seen Finn take on in the show? How do I model the way Finn behaves in a game?