!!Theories involving Haine!!

* He's Yami Marik having survived the Shadow Realm and possessed a child.
* He's [[WebVideo/YuGiOhTheAbridgedSeries Mr Tweetums]].
* He's Mokuba
* He's Yami Bakura.

!!Theories involving Playable Characters!!

* Roxas is secretly Apophis.

** '''''YOU FIEND!!!!'''''

!!Theories Involving David Kinrab

* David is an emissary of one or more of the Gods. If he's on the side of good, then his Spellcaster deck and deceptive nature likely means he's a servant of [[MagnificentBitch Isis]]. If he's on the side of evil however, chances are he's working for the creatures that Apophis has sealed.
* David is an {{Expy}} of Rei Shingetsu[[spoiler: /Vector]] from ZEXAL.

!!Theories Involving "Ishmorne"