Thread:PeaVZ108/@comment-26888167-20180410034557/@comment-26888167-20180410042640

Well, actually, it does. The problem is that using it will free Captain Dark Shell. You see, the ancient shadow ninjas made this amulet to contain the most powerful shadow powers ever known. However, when Captain Dark Shell became such a tremendous threat to everyone, they had to use the power of the amulet to seal him away forever.

The amulet still contains the shadow powers the book mentioned. The problem is that using it will free Captain Dark Shell from his imprisonment. If Captain Dark Shell didn't have to be sealed away, the amulet could be used for it's power.