I wish they would just say if he was coming out here or not. ![Angry >:(](https://www.jedidefender.com/yabbse/Smileys/classic/angry.gif)
There is no official comment from Hasbro, but all signs are indicating that the Wave 4 mix case may end up like the 2013 Movie Heroes line - only available OUS.
So far, US accounts have only been offered the solid cases of Raddus, Galen, or Sefla.
Barring some sort of product dump at Five Below a year from now (or some other distribution change), your best bet at securing a Fenn Rau right now is going to be overseas etailer order, ebay/secondary market, or finding a nice Canadian who might be willing to help you track one down.