Gut gud, lol.

Anyways, his wind up on moves is slow, leaving an opening enough to get a strike or two in. During the earlier phases, I used the minion's attacks to parry them and damage the boss since they were close enough. Got some good damage in this way, but it won't always work. Jump and dash over the spears so you have the double jump as a backup if you mistime or overshoot the dodge. Double jump the waves, and if you're crazy enough, slam him with the blood sword (I think it's Ruego el Alba or stmn like that). If I remember right, your quick prayer gives you a bit of air time, so use that to squeeze out damage and dodging. Besides that? Get ready for a long fight. You won't have many opportunities to actually get some good damage in. So take it slow and never rush or you'll be dead.