This dude is INSANE. He has infinite stamina, much better armor than me, much better stats… I’ve tried at least 50 times now and the best I got is 50% of his health. I have no potions, my helmet and chain coif are broken, I have no chest armor and the only decent armor I have is on my legs. Strenght stat is 3. I have a sword and shield, full health, suprisingly. I’m ok at combat but I didn’t train too much so I only have the perfect block and the first combo you learn. I wouldn’t really like to load an older save because it’d lose me a lot of progress and time. I’m super pissed because of it, because I don’t think I’ll literally ever beat him. This is what I imagine Dark Souls is like. I’m honestly contemplating not wasting my time on this game anymore and quitting it to go play something else. I think it’s a great game but spending 5h on every boss is not my cup of tea. Any tips except “git good” would be appreciated, thanks.
First boss … does he have a name? Where did u met him?
Runt. Not the one in Skalitz.
Level up.
If not, stab, stab, stab at his head, and maybe you can get lucky. Maybe.
There u have ur answer… haha 
Well, to the point… there are several ways: get good armor, good sword and stab, stab, stab. You can use archery too… one arrow to the head will suffice while u try to keep distance. Dont melee if ur have low stats
Only real problem for many players is to rush… no need to rush, enjoy the game. 
The only way you could have gotten to that point in the game with 3 strength is to have completely avoided all combat. I’d be surprised if you even managed to complete the combat tutorials. Were you trying to avoid combat?
This means that you lack the skill to be any good at the combat, and your character lacks the stats to make up for that lack of skill. So, how do you beat someone that isn’t wearing a helmet? You can poison an arrow and shoot him in the head. Then just defend. You can get good. You can get better gear. Work it out, there are no participation awards here.
This is the only combat you have to win in the game. It’s poor design IMO. In the beta, you could lose this fight, and the game continued. You could also just run away and let the soldiers kill him. Instead, in a game that mostly lets the player choose how to play, they are forced into a single outcome. Fight in the roof a building with no exits. It makes no sense. How did you get in? Why can’t you get out? What are the soldiers doing while Henry is doing this?
lol. You could get chest or other armor from corpses before cutscene. But you really need potions - it would be logicly buy it getting to battle. Use cheats if you don’t want to load an older save.
Bane potion - poison what guaranteed kill him.
cheat_add_item id: 42e54d97-6e63-4e50-a09d-325ef4dd2286
Aqua Vitalis - 50% dmg
cheat_add_item id: 850d28d9-9d0a-4b2e-9feb-e6c48c5f1aad
Also you may try to use AI weakness. Get and win in clinch - win in clinch makes possible to one hit, enemies never block it.
Do it what do you want, but just one time think about it.
If this is the first time you’re meeting Runt, you’re not meant to kill him. Just lose and progress the story further.