Chapter 15

Right at the start of the level, look to your right to see another hallway. Jump over to it as a beast. At the end is another chest.

Right past the Gates of Hell, you'll see some floating platforms. Instead of jumping on them, run to the end of the hall to the right of you to find the next chest.

After getting Chest #41, jump on those floating platforms. Once at the top, run straight ahead and you'll find another opening in the ground. Drop down and run to the end to find another chest.

After you activate those platforms after turning the key on the blue cylinder, head straight ahead past the first safety platforms to the next set of safety platforms. There's a lone platform nearby that has the next chest.

Right from where you are, move the camera around and you'll spot another chest. Fly over to it as a crow to open it.