User blog comment:Zoroark555/Who Is Your True Buddy?/@comment-3974145-20160329212057/@comment-3974145-20160329212913

I should also note as an extra, that certain alternate forms of cards are also likely one of a kind. Example, Fifth Omni Drum, this monster only existed in one Drum and chances are super impossible that is can ever be duplicated in another.

Though some Alt forms I believe though maybe can happen to other Drums. Example, Thunder Knight Drum, it is a very high chance that other Drum Bunker Dragons outside the anime's Drum have also trained as Thunder Knights too. Though Alt forms for different Worlds are very likely not to be like Decker Drum or Brave Drum since Drum Dragons do not normally exist in these worlds. Maybe Neo Drum of SDW? idk cause it could be possible for the Drum species to still exist in the future world of Dragon World.

[oh and yes I know I used Drum a lot in these examples, well he just makes it easy by being in the anime and have so many forms :P]