D/D

"DD" ( DīDī) is an archetype used by Reiji Akaba in the special Yu-Gi-Oh! ARC-V chapter and anime. It is supported by its own sub-archetype "DDD". So far, they are all DARK Fiend-Type, except for the Extra Deck monsters, which have a different Attribute each.

Design
The regular "DD" monsters seem to be based in different figures and monsters from Western mythology, such as Chevaliers, Lilith, Ogres, Cerberus, etc.

In contrast, the "DDD" sub-archetype features a distinct design style from the rest of the archetype, with its members modeled after famous conquerors from world history.

Taken together with its subordinate and sub-archetypes, the "DD" archetype features a mild "business" sub-theme (probably to fit the profession of their owner in the anime), with many support cards referencing elements of modern big business. For example the "Covenant" cards resemble business contracts, and the names of "DDD Resource Management" and "Lease Laundering" reference like-named company practices. Plus, the boss monster for the entire Archetype, "DDD Hell Armageddon the Cruel End Overlord" features a pun in its Japanese name– "Great Des (Death) Lord" is scripted as "Shiiō", a homophone for "CEO."

Etymology
According to Sora Shiun'in, "DD" is short for "Different Dimension" (ディファレント・ディメンション Difarento Dimenshon).

Playing style
"DD" monsters revolve around utilizing efficient searching and swarming effects to Summon Fusion, Synchro, Xyz and Pendulum Monsters, as well as manipulating "Covenant" Continuous Spell and Trap Cards to reap their benefits and evade their drawbacks. They also include numerous effects to recover lost "DD" and "Covenant" cards from the Graveyard.

This deck's primary playing style is massive summons using "Temujin" and "Alexander" and high-level Synchro monsters with "Night Howling" (It should be noted that the DD monsters should preferably be Special Summoned with "Alexander" or "Temujin," not with "Night Howling," as that would restrict what monsters can be Summoned). One can easily get 7000 ATK damage on the board. Since Pendulum monster counteract putting them into the grave, it is best to use "Covenant with the Dark Witch," "Kuribandit", "Hand Destruction" and/or "Needlebug Nest" to put them in the Graveyard from the Deck and hand.

The Deck also has considerable draw power, putting good use to cards such as "Hand Destruction," "Magic Planter," "Lease Laundering," and "Allure of Darkness." "Magic Planter" can be used to evade the drawbacks of "Covenant" Continuous Traps, and "Emergency Provisions" can also be used to regain lost Life Points and stay in the lead.

This deck has a few major weaknesses. First, this deck is built for pushing for game, so decks that counter swarming ("Fossil Dyna Pachycephalo", "Black Horn of Heaven", etc...) can hurt this deck. It's own weakness include the Covenant cards themselves. Having all 3 out takes 3000 damage each turn, although "Lease Laundering" and "DDD Leonidas the Rebellious Lord" can mitigate the costs. Finally, "Fire Hand"/"Ice Hand" pose the biggest threat to this deck, and should be best handled using "Soul Drain", and most of this deck's effects activate on the field.