Ranks are based on the amount of wins you have. Your win/loss rate does not effect your rank. Ranks do not offer anything extra concerning skills/stats. Aside from special ranks (Staff and Admin), they are based off of your total wins (excluding NPC wins). The sign next to your battle record changes every time your rank goes up and corresponds to the Rank upgradeable achievement. Here is the list of currently known ranks. There is no picture for Civilian Rank because there is no symbol.
The following are staff ranks. These ranks are only available to the moderators and administrators of EpicDuel.