Just parry and kill him, if not get good.

I find a strategy that does not work every but close: let him close distance, R1 attack him when he's a little bit too far, so you'll miss, immediately follow up with a gun attack. The missed R1 attack lure him to attack you and the gunshot parry him, allowing a visceral attack. I managed to "visceral" him three times (and regain health in the process wth the Caryll rune).

I find this by watching him parrying me with this stragery several time : he make an attack that leaves him open, so you charge in, he'll parry, you're dead. So throw him back his own medecine.

this guy walked so the godskin duo could run

This fight takes the problems with the other hunter fights (hitting ridiculously hard, being damage sponges, infinite ammo) and dials it up to 11. His pistol can easily kill you in one or two hits and his melee attacks hit almost as hard. On top of that, he is a damage sponge that can heal (even if it's only once per fight). Unlike most of the other encounters in the game, this one feels neither fair nor fun. It's like they asked the night janitor to come up with a way to make the fight challenging and just took their first idea

Mathematically speaking, if you kill a host you get 10% of their last level cost, 30% if it's an invader. If you consider this guy a "host," he is around LVL 100. If you consider him an "invader," he is around LVL 60.

Either way mf is hard.

The most cheesy way to beat him is to lure him to the the door entrance , he will keep runing to you in place because his Ai prevent him from going outside the door, just run to him with charged attack, repeat, until he die.

Boom Hammer this dude to death with jump attacks and flinging fire

If you jump at him while he's running towards you, if you've put enough distance between him then you can jump attack with the primed hammer and knock him down without a trade

Just do that over and over again and he'll die in no time. If he ever gets too close for a jump attack, use the primed uncharged R2 to chuck fire at him; this will stun him and give you enough time to reposition yourself

Ah sweet input reading parries

I managed to get him first try. I think I got really lucky with my parries.

Found a pretty funny strategy with the Gatling Gun. Melee fight him until he's at about 2/3 health. Wait for him to transform his weapon then ****ing UNLOAD on him. Literally don't stop walking towards him and holding L2 and he can't do anything til you run out of bullets. With a +6 gun, 20 BLT, Formless Oedon and blood bullets I was able to take him down to a tiny sliver of health before I ran out of ammo. Then just bully him to death while he tries to back off and heal. Though if you have more gun damage than I did you'll probably just kill him outright before you run out of bullets.