>>280121359
You are seeing King Gaesric memories which from his armor and backstory is heavily implied to be skull knight.
He's also been turned into an undead by the armor and we are shown around the same time he has a sword made of behelits (you know, the reality-bending artifacts).
It is said and shown several times Guts will lose himself or do unfixable damage to his body if he keeps the armor.
The picture is pretty clear to me. Skull Knight has been crusading against the God Hand for who knows how much time in a hopeless quest for revenge.
If you are disappointed about the "powerlevel", well, they are evil deities empowered by fate, it's not a fair fight. And even if you kill them, they just make new ones, as I said, so it doesn't really matter, though you might believe you did something and you can fight against this evil destiny (reminds you of something, right?).
As for how you really fight against the God Hand, I imagine you go for the heart. Who knows how that works.
It's a more interesting theory than just assuming it's an internship position and they get rid of you when they find another grunt, if you ask me.