I just did some more checking, and evidently there must be a major glitch, because I broke the seal in the royal gardens. So I can either start over and hope it doesn't happen again, or better yet get rid of the game.
The second mask you need is in the Denguey Forest Tower. It shows up as a black looking cross on the map. I was thinking it was glitched too until I saw the X1 on the map when you highlight the Sealed door. --- I thought you said something about being entertaining cause that was boring. You're not funny and nobody likes you. -CM Punk
I too though this was a big glitch. I ran around forever to trying understand. I never noticed the mask before I read these posts, near the great tree. I also read the same walkthrough and I know what you mean, the author didn't spend much time on the walkthrough. To assist any others who may read this: In the Denguery forest Tower, open the doornin front of the strange red u shaped looking rock on your map. Enter with Majin. Go to the wall with the salamander and have Majin crouch, go counter clock wise around the upper rock/ledge and pull the lever to make the door come down. Now jump onto the top of the door, once there signal Majin to open the door you are standing on it will lift you up to reach the second mask. Watch out for the smog trap on your way down.