Putrid Knight might be the worst boss in Elden Ring, and when compared to the ones with a Remembrance, it's for sure the worst by far.
Looks like shit, is annoying to fight as he is always moving away from you and his fire attack is a pain in the ass. I just hated him. Thankfully he is weak, so I didn't hate to fight him for too long.
He is so bad I'd put him in the same tier as some of the worst bosses from DaS2.
On another note, I found Bayle. I assume he is the "ultimate challenge" of this DLC, based on how little damage I did to him and also on the fact that From loves to have big dragons as their "ultimate challenge". Kalameet, Midir, and I guess Sinh to a certain degree. I still need more Scadutree levels to have a chance against him. But it's cool that you can fight him almost as soon as you enter the DLC.