"Void", known as "Purgatory" (煉獄, Rengoku) in the Japanese version, is an archetype of Spell/Trap Cards that support the "Infernoid" archetype, the first support for which was introduced in Crossed Souls.
"Unformed Void" is not a "Void" card because its Japanese name does not contain 「煉獄」. In addition, due to the opposite reason, "Blast Magician" is also a member of this archetype. However, because TCG/OCG support for this archetype only works on Spell and Trap Cards, this is not an issue, unless they are treated as Equip Cards.