SINNER: Sacrifice for Redemption

To fight “Slothful Yordo”, you will sacrifice your stamina. You will become exhausted and stay still for a few second when you use up all your stamina.
Don’t bother killing the soldiers, they are infinite. I recommend logging on to Yordo (he wears different helmet) all the time and try to separate him from his soldiers.
Earlier in the fight, two effective way to land hits on him is either rush attack or parrying.
- Rush attack is done by running toward him by hold RT and hit X (recommend using sword sword). His attack is slow and he won’t have enough time to counter you. Whether you land a hit or not, keep on hitting him. If you done enough damage to his shield, it will break and he won’t be able to block
- Learn the timing of the boss attack and try to parry it. If you success in parrying, move forward a bit and press X to do a stabbing animation. You are invincible during this animation but as soon as he falls down, the other soldiers will rush at you. Quickly roll forward toward the boss to avoid solider attack. If you are lucky, it sometimes give you room to breathe so you can land a few more hit on him.
Later on when he summon group of enemies to circle around himself, you can through spear to disburse the group or throw fire bomb at the group.
Save your spears and use them when his health is below 30%. He rarely dodges your spears.

Credit: The video is not mine and credit goes to the real creator. The video has comments from the creator which give you more detail strategies on how to beat the boss.