Sorry guys you can't breed it so far. I don't know which 'basic' element we need to breed for, but I thought let's give it a try with mythic and water. And it worked for me at my first try (lucky me).
Probably we need this creature for the SB, so that chapter will tell us what we need to breed for. All I can say is continue breeding in the meantime and hoping you all get it soon. Wishing you all the best of luck.