This will be one HELL of a fight. I'm talking end of the season, pull out all the stops, no-holds-barred. But...
Kaioh will win.
No matter how strong Raoh, or any user of Hokuto Shinken is for that matter, will become, Kaioh's Hokuto Ryuuken style will always be superior. He even demonstrated that his style absorbs the force of all others (I'll post videos later), making any attack virtually useless. Added to this, he can bend his opponent's perception of reality and he can use black magic! Even if Raoh uses Musou Tensei, it'll be impossible to use against Kaioh's incantation spells and the pressure point business is out due to Kaioh's principle of "I hurt you, you can't hurt me." Besides, Kaioh f***s Kenshiro up like no-one else has before.
Raoh, basically, is climbing up a waterfall without an HM.