Board Thread:Tips, Tricks, and Questions/@comment-22528869-20130922215219/@comment-128.189.247.95-20130927172233

You can't have a monster with 2 different elements. Monsters must be evolved with itself. "Fusing" is just a way of leveling up your monsters, and does not contribute to adding an element. (However, if you fuse commons with the same element, you sometimes get a bonus.)