So far in the ARC-V manga, the "D/D" monsters appear to be demons with a mechanical, scientific theme (distinct in design to the "D/D Savant" monsters) and have equipment like scales or microscopes instead of faces.
According to Sora Perse, "D/D" is short for "Different Dimension" (ディファレント・ディメンション Difarento Dimenshon), the same as the "D.D." series.
Either "Lamia"s or "Siegfried"s effect can used to Bounce or Negate without destroying to avoid the cost of the "Dark Contract" cards for a turn or use the effects of "Oracle King d'Arc" (turns effect damage into gain LP) and "Rebel King Leonidas" (Disables effect damage) to disable the LP payments permanently.
The following Decklists may or may not contain copies of cards that exceed the maximum amount allowed by the current Forbidden & Limited List. These should not be changed, as these Decklists are copied verbatim at the time they were published.
Because this Deck focuses on swarming to push the game, cards that can disable or counter swarming or searching, like "Fossil Dyna Pachycephalo" or "Thunder King Rai-Oh", can greatly hinder this Deck. Additionally, the archetype's synergy with the "Dark Contract" archetype provides a weakness to Spell/Trap removal, as well as a dependence on cards that mitigate the damage from the "Dark Contract" cards.