Impure Summon

Impure Summon is a type of Summon introduced in Starter Deck D-ZERO, but was revamped in Starter Deck D-ZERO 2017 Q2 and appears in ''Yu-Gi-Oh! D-ZERO  and Yu-Gi-Oh! D-ZERO II''.

Prior to Duelist of Chaos:
If a player controls an appropriate Material for an Impure Monster, they can flip that monster face-down, then stack the Impure Monster on top of it, akin to an Xyz Summon called the monster's "Soul". Impure Summon currently can only be conducted once per turn. If the Materials in the Soul of monster are removed or if the monster is no longer on the field, those Materials are sent to the Graveyard.

Post-Duelist of Chaos:
Impure Monsters are no longer once per turn and they no longer flip monsters face-down to Summon. The method to Summoning an Impure Monster remains the same, although now a player can use more than one. All Impure Monsters Summoned this way, must have their Impure Materials' Level sum match exactly the Negative Level of the Impure Monster, akin to Synchro Summon. However, Impure Summon now comes with a cost that sends cards to the Graveyard equal to the number of monsters used to Summon the monster. Example: 1 Level 3 "" + 1 Level 4 "" = Negative Level 7 "Rift Beast - Dimension Zero Dragon" or 1 Level 7 "Rift Beast - Zero Burst Dragon" = Negative Level 7 "Rift Beast - Dimension Zero Dragon". However the cost from the hand for using such monsters is the same cards as the monsters used to Summon (2 for the former method and 1 for the latter method). This allows multiple Impure Monsters to be Summoned in a turn, albeit as long as one has the required number of cards in their hand, but less chances to use their effects, as most Impure Monsters from Duelist of Chaos onwards will require to remove cards from their Souls. This is changed to "deleting" Impure Materials. Starting from Starter Deck 2017: Reloaded onwards, Impure Summoning will no longer have the discard cost.

In Yu-Gi-Oh! D-ZERO
In ''Yu-Gi-Oh! D-ZERO'', Impure Summon appears as a monster is enveloped by darkness and surrounded by a black sphere (in Luna's case, the sphere has the Mark of Cain symbol) before the monster erupts from the sphere into its form.

In its sequel, a DNA double-helix is fired out of the player's finger. The Impure Materials then fly into the air and turn into spheres. The spheres then turn liquid-like and coat base pairs on the helix at random. The helix then explodes into blood and atoms before reassembling into the monster's form. Luna's Eye/Etro's Gate can be seen for a brief second in Luna's version.