In order to access the Secret Area in Chapter 4, you need to kill a boss a few times. So you’re going to start at the pool of Shattered Jade and follow the route around the corner through the giant egg sacs until you see the massive egg sac in the middle of the room. Go ahead and start hitting it and eventually that exact will break, allowing you to start the first phase of the boss fight. Defeat that portion of the boss fight, and he’s going to run away from you and you’re not going to see him again until later on into chapter 4. Moving into the court of illumination shrine, you’re then gonna follow this route that I’m showing you, pretty much going straight and hanging a left every single time you see a tree until you come to an area that’s super steep and opens up into a massive room. This is gonna be the second portion of your boss fight, which is going to be a multi phase fight. But once you kill him, you’re going to get a few items and then you will look over at the wall and have the ability to interact with it. Once you interact with the wall, the wall will melt away and you can enter the secret area going into Chapter 4. There’s a few really awesome items and great quest lines in this area, so I definitely recommend doing this boss so you can get This entire portion of the game opened up to snag these items.