Numbers D (Dark Numbers)
Dark Numbers (D No. in the OCG) are a subtype to Number archetype. they appear (or are planned to) in a Pokémon x Yu-Gi-Oh! Arc-V crossover fic titled "Pokémon Arc-V! Flaming Soul!" and are created by Genesis Omega Dragon after he stole the Numeron Code from Astral. the Over-Hundred Number are retconned to being Dark Nmubers of their mythyrian Number counterpart, Don Thousand's Numeron cards are also retconned into Dark Numbers.
unlike some of the other Numbers, Dark Numbers aren't exclusively Xyz Monsters, in fact, they could range from Ritual Monsters all the way to Link Monsters, though the links won't be included in the fic.