At this point in the game, it is the most difficult fight you'll have to do. This boss has
2 phases, the first being much harder than the second
A little video to help you
First Phase: Be
patient. The easier way is to
run around the boss, and hit when you are behind him. It will be a little bit long, but it's easy and pretty safe (and you're not a speedrunner). You also can use the firecrackers but not too much! You will need some emblems for the second phase.
Second Phase: Also be
patient, this is an easy phase but if you're not patient, you will die quickly. Just (perfect)
deflect his hits, and use the
Loaded Spears when he is vulnerable after a combo. If he use his scream, just run (don't jump!) and use a Pacifying Agent to be safe (you can farm these ones on the Abandoned Dungeon)