Parting Ways...?

As I opened the door to the cabin my mother and father were staying in, I found it deserted. It was completely empty, and the only traces of someone ever living there were the used cookware. 

Frowning, I walked over to the table where the letter was left, and picked it up and read it.

Dear Kai Kai.

If you are reading this, then chances are your mother and I have already departed. Do not come searching for us. Where we went is a very dangerous place, and with your current understanding of Chaos, you cannot enter. Furthermore, to prevent you from trying to track us down and following us, your mother and I have decided to set a lock in place below this cabin. The key lies with you and Xuan Yu, working together. When the two of you have truly bonded and the powers of Chaos and Order within you have grown to unison, will be when you can come searching for us once more.