Fictional character? Iunno... there's so much to pick from. Guess it kinda revolves around whether you want to play the short or long game.
Short game is survival. Examples of good survival peeps are The Thing, TF2's The Sniper, several Norse gods and... hell, everyone from the various mythologies around the world. Gotta be at least some badass people there. Hadda pick one of those, I'd go with Fergus from Irish myth. A guy with a sword that can slice entire hills in half is pretty good going.
Long game involves reconstruction; building a haven city and defending it with things built out of rusting scrap. People I have in mind are Nikola Tesla (the Atomic Robo edition), or one of the engineering geniuses that inhabit scifi stories the world over, or maybe someone else entirely. I do the politicking, he does the building, and our legion of robots does the heavy lifting and zombie/bandit repulsion thing.