u/Humble-Newt-1472

I'm about 3 or so hours into this game and I'm not quite sure what to do. This boss has a metric shitload of health, it feels like, and does half my health if I miss any parries. Can't even leave the fight, my body just keeps getting stuck in the boss arena so I gotta finish the encounter.
Compared to the other two bosses I've fought, both in the Power Reservoir (guy with big spear & centaur), this feels intense. Not normally one to come to reddit for advice, but any tips?