Elden Ring Putrescent Knight Location

Hey everyone. So i just got done with almost every remembrance boss I think, and the only one left is the putrescent knight. However, I have no clue where he is, and I've searched way too long. pls help
 
Boss is at the southwestern edge of the Cerulean Coast. You'll need to follow the road to that massive hole at the edge, then drop down, and then it's a straight route to the boss.
 
Also as an extension to my answer: you can get to the cerulean coast via the poison swamp southeast of the castle front site of grace
 
Its a lengthy trail to him, also make sure to break the seal in chasm here by reaching the shadowkeep dungeon