Milo James Thatch is the protagonist of Disney's 2001 animated feature film, Atlantis: The Lost Empire and its 2003 direct-to-video sequel. He serves as a linguist and cartography expert who directs the expedition to find the lost continent of Atlantis.
Vote which fictional character would naturally fit in-universe with a big-named franchise! No time-travel, no interdimensional crap, no "Pooh's Adventures", they would just exist in-universe.