Entity

"Entity" is a series of cards introduced in Legacy of the Valiant. They are a series of cards based around H.P.Lovecraft's Cthulhu Mythos, and consists of three archetypes: Elder Entity Fusion Monsters, Old Entity Synchro Monsters, and Outer Entity Xyz Monsters.

Playing Style
The deck is based around the synergy between the archtype's Fusion Monsters, Synchro Monsters, and Xyz Monsters. The main purpose of the deck is to overlay a Fusion Monster and a Synchro Monster to summon "Outer Entity Nyarla," who is then used to summon "Outer Entity Azathoth," who can use its effect to destroy all cards on the opponent's field if it has all three monster types as its Xyz Materials.

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 overlay units to use it's effect, 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 keep re-summoning "Norden" and thus keep recycling it's 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 problem getting those Fusion Materials into play at once, and if a Synchro monster is used for the fusion, "Norden" can revive it once summoned. "Fusion Substitute" 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 affords the player when repeatedly used for Xyz and Fusion summons.

"Norden" only needs "Instant Fusion" or "The Unspeakable 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," "Goblindbergh," and an assortment of other Level 4 Warrior-types and Level 1 Tuner monsters, all work to quickly summon 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. 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.