Board Thread:General Discussion/@comment-174.49.208.85-20130523231215/@comment-28736333-20130529214025

My theory: The gem in the middle protects us from the shadows, but in 2014/2015, Tusk returns and now he can master shadows, Sensei convinces him to join the good Ninjas, and no longer be enemies, and Tusk decides to join him, Tusk allies with Sensei and they both teach us the element of Shadows