I did that on accident with Scorpionlord. He smashed me over and over again with his long combos and crazy reach. Decided to come back and try later. Oopsies. I actually never beat him.
I certainly died to Yellow Loong a handful of times, I just don't remember struggling with him. I feel like he had a pretty small moveset and got his rhythm down pretty quick.
I also ground out some serious levels at the spider cocoons so I could unlock all of my desired skills and not have to bounce attributes back and forth for different scenarios, so I was pretty beefy going into the end of Chapter 4.