Entity " Entity " is a series of Extra Deck monsters introduced in " Legacy of the Valiant " . Design . This series is based on cosmic entities in ' s " " . The " Elder Entities " are based off the , the " Old Entities " are based off the , and the " Outer Entities " are based off the the . Playing style . The Deck is based around the synergy between the archetype ' s Fusion , Synchro and Xyz Monsters . The main purpose of the deck is to overlay a Fusion Monster and a Synchro Monster to Xyz Summon " Outer Entity Nyarla " , who is then used to Summon " Outer Entity Azzathoth " , who can use its effect to destroy all cards the opponent control s if it has all three monster types as its Xyz Material s . The simplest way to Summon " Azathoth " and be able to use its effect is to use " Instant Fusion " to Summon " Elder Entity Norden " and use its effect to revive " Old Entity Chthugha " or " Old Entity Hastorr " , then overlay them into " Nyarla " and then " Azathoth " . Because " Azathoth " needs a Fusion Monster , Synchro Monster , and Xyz Monster as its Xyz Materials to use its effect , and needs to detach one to activate it , it will usually only be able to use that effect once ; " Xyz Override " and " Xyz Unit " can be used to allow " Azathoth " to use its effect multiple times . Reliance on " Norden " for this Deck is important , as it can allow the Summon of " Azathoth " single - handedly by Special Summoning a Level 4 Synchro Monster so " Nyarla " can be Summoned . " Re - Fusion " and " Call of the Haunted " are useful to continue Summoning " Norden " and thus keep reusing its effect . " Norden " can also be Summoned by its normal method , using " Polymerization " to fuse two Synchro and / or Xyz Monsters , as the Deck should not have problems getting those Fusion Materials into play at once , and if a Synchro Monster is used as a Fusion Material , " Norden " can revive it once Summoned . " Fusion Substitute " or " Flash Fusion " can be used instead of " Polymerization " , since any monsters to be fused will not come from the hand . Other than " Norden " , " Cthugha " is another important card due to the draw power it provides the player when repeatedly used for Xyz and Fusion Summons . " Norden " only needs " Instant Fusion " or " Forbidden Trapezohedron " to be Summoned , which can be worked into any Deck , and " Nyarla " is best used with " Cthugha " or " Hastorr " as its Xyz Materials . Thus , any main Deck theme that can reliably Summon Level 4 Synchro Monsters will work as support for the series , as long as the mentioned Spell Cards for Summoning " Norden " are also included . One potential Deck for use is a Warrior Deck . " Marauding Captain " and " Junk Synchron " allow for the quick summoning of monsters to set up for the summoning Level 4 Synchro Monsters and Rank 4 Xyz Monsters . The Deck ' s access to " Reinforcements of the Army " and " The Warrior Returning Alive " also increases flexibility depending on what type of monster the player needs . " Doppelwarrior " and " Tuningware " are also useful in getting Level 1 and / or Level 2 monsters into play for Synchro Summons . " Synchro Fusionist " is an excellent support card for this deck , allowing the searching of " Instant Fusion " and " Re - Fusion . " Beyond this , Level 3 and 4 monsters that can change their Levels are useful , if the player needs a Level 3 monster to go with a Tuner for a Synchro Summon , or a Level 4 monster for an Xyz Summon . Weaknesses . The Deck ' s major problem is consistency — the unusual combination of cards needed to support so many different summoning methods means the player may have a hand full of cards that do not work together to accomplish the Deck ' s objective . The reliance on quickly performing these Summons also makes the Deck bad for hand advantage , and their momentum can be halted if the opponent is able to stop their combo in progress . The size of the Extra Deck is also a problem — the player is unlikely to have much room for monsters outside the " Entity " theme , and thus their deck may lack versatility . " Daigusto Emeral " is a useful tech option to return the player ' s cards to the Extra Deck in a pinch , allowing the player to run fewer copies of them and include more Synchro and Xyz Monsters that can support the deck .