HELP! (Spoilers alert)

Guys i need help… (Spoilers alert) I’m fighting this guy with half my health and he is so incredibly OP that i can not defeat him, im probably doing something wrong… the game already glitched some times where the duel with him will start and then the battle will end because all man died so i dont want to go back to my other save before this one

Update: i defeated him by performing a glitch in were i used some barrels to create a space between me and him and used a bow to headshot him… so now maybe this topic can be moved to the bug reports