Don't you have 0 troops if you run from combat?

You get your starting army - the same when you start the game... + some money (depends on your level na difficulty you are playing). You won't have 0 army... :)

Playing an impossible warrior game and I'm up to level 16, intellect is 5. I entered the range with 1 Sprite which left me with no troops. I then retrieved 1059 Sprites and 457 Dryads from my reserve and completed the range with no losses.