Demise and Ruin are two series of Ritual Monsters (one composed of DARK Fiends and the other of female LIGHT Fairies), that originally debuted in Shadow of Infinity and were later expanded in Cybernetic Horizon. The original monsters of the theme—"Demise, King of Armageddon" and "Ruin, Queen of Oblivion"—were unique in that they were linked by a Ritual Spell Card, "End of the World".
Despite both monsters appearing to be the wielders of the power of destruction and an antithesis toward each other (as seen in "End of the World", "Cycle of the World",and "Turning of the World"), they seem to share a relationship of some sort due to Demise always appearing as a shadow in Ruin's artwork, matching each of her stages.
|Young||Agent of Armageddon||Angel of Oblivion|
|Middle||King of Armageddon||Queen of Oblivion|
|Advance||Supreme King of Armageddon||Supreme Queen of Oblivion|
The goal of the deck is to quickly Summon the Level 10 version of both Demise and Ruin to overpower the opponent, providing destruction immunity, clearing the field, and performing an OTK, using the Level 4 version's effects to prevent the opponent from responding to attacks or effect activations.
"Pre-Preparation of Rites", while useful, requires you to have at least one of the original versions of either monster in the Deck as both Ritual Spell Cards only state the original version's name. Similarly, you cannot activate the second effect of "Endless of the World" unless the original version of either monsters is in the Graveyard.
The "Impcantation" monsters can be easily used to fulfill the tribute requirement (due to their combined level being 10) while providing the player more resources to perform additional Ritual Summon.
"Djinn" monsters are also ideal that they can banish themselves from the graveyard as part for a Ritual Summon and can grant additional effects to the summoned Ritual monster.