Wow this fucking dumbass. You cant go to the capital? Just fucking go around it, its an open world where you can go where ever the map exists.
IF, and I mean IF!!, the game designers are that stupid that they pop an area boss in the ONLY path to the capital from the starting zone, the they would get ROASTED to hell and back for this ridiculously stupid design choice.
Otherwise, just don't bloody attack it, run away and keep like what, 1 KM distance and since you can run without getting low on stamina, just f''n keep going dude.