Originally Posted by dukemon22

So these two names have been thrown around for a bit, and a rumor may explain the relation between them:
Emperor Form is the next form in the Kiva evolution, resulting from the absorption of all the Checkmate 4 into Castle Dran.
Castling Form is a warped version of Emperor form, resulting in Kiva loosing control of his power in that form.

Also, according to rumor, Kiva will get 1 more form in November, but nothing is known about that yet.