This is the Ninjago mask at original minifigure scale. This WILL work for a jumbo minifigure, but will require scaling to 410% if you plan on removing it from the blank_head.
Update: Added the additional files needed to complete your Ninjago figure. Again, scale up for Jumbo figures... except 405% should do just fine.
Ninjago_Mask.stl | 187.7KB | |
Ninjago_Shoulders.stl | 63.4KB | |
Ninjago_Sword.stl | 85.9KB |