Likely never. The big new cards in the Doma Arc (Air Fortress Ziggurat, Gorlab, Guardian Dreadscythe, the various Armors, the Orichalcos cards) have yet to ever reach the public, with the only exception I can think of being Guardian Eatos, which has a nerfed effect and only exists as a promo in Japan. All the others already existed. Next, the Legendary Dragons have such spectacularly open-ended effects, that even if the others made it out of vaporware, they likely never would. And finally, BETD was formed by fusing Blue-Eyes and Tyrant Burst Dragon, which is, itself, a fusion of two cards (there are only two cards in the metagame that fuse fusions), and neither of which exist yet! So, in short, never. Why would you want it anyway? The Doma Arc sucked.