Board Thread:Grimm News/@comment-204.38.138.55-20170201000246/@comment-27399661-20170321133845

Kelly is indeed special, he will not be as powerful as Diana (which was confirmed by Bitsie during a FB live chat) but most likely more than Nick and Adalind.

I'm sure Kelly's blood is also very special. Also he is an abomination especially to the Wesen world.