Well Ganon according to Demise’ Curse is his Hatred Incarnate.. which means yes Demise could control his Hatred Incarnate. Nice!indeed. Demise came in the form of Ganondorf, because that was the form he had taken before.
also, something I forgot to mention in he work, but is really important. demise could only speak to ganondorf. the possession could only occur after the master sword had been pulled.
Ah you see Ganon and Ganondorf as separate. I see them as one. Reason:well, ganon, yes, not Ganondorf. Ganondorf is the host.
There's some cool 3 goddess and sacred realm images from official artwork, or fanart too could work if you credit the fan artistsok good to know. Also, I wouldn't have, It's just the best images I could get.