The goal of this is to practically shut down the game or beat up the opponent quickly depending on what happens early on.Note that the extra deck is a  work-in-progress and the side deck is not actually a side deck but just cards that I have thought about using/was using before.

Ideal Scenario Strategy

Ideally, the opponent sets up a board on turn 1.

1. Then by some means (naturally draw, Terraforming, or Ahrima, King of Wickedness )  get 2 copies of Lair of Darkness in hand, get at least one to actually stay on the field (2 cards out of the starting 6).


2. Next, tribute an opponent's monster to summon Duke Shade, King of the Umbra(card #3).


3.  Then normal summon Ahrima (card #4),  and use it's effect to tribute Duke and search for the 2000 or more defense-criteria meeting Darkest Diabolos, Lord of the Lair. Since the tribute for Ahrima went to your grave, you can summon Diabolos right off the search effect.


4. At this point, you are left with 2 other cards in hand, with Ahrima and Diabolos on the board, allowing you to attack for potentially 4700 on turn 2. In main phase 2, tribute Ahrima with Diabolos to drain the opponents hand by 1 (of their choice) back to deck. Set whatever traps you have from cards #5 and 6. End the turn, get 3 1k/1k Torment Tokens in defense or watch Lair get hit by Ghost Ogre and Snow Rabbit. (they can not hit Lair with GO until it actively triggers in the end phase) This potentially will disrupt the opponent enough (especially if you have a virus available) that they either accomplish nothing the next turn, or they spend so many resources to reset the game state that they can not deal with your second Lair on turn #4.

Most of the time, you will be missing some piece of this combo, having a set monster on the opponents field which you can not tribute, or they will be able to Ash Blossom and Joyous Spring Ahrima's search when you did not have Lair or Diabolos in hand. Also, since you are going second, you will be vulnerable to counter traps like Solemn Strike.

Other Notes on the main trick of the deck

• Monster Reborn, if you have it, will allow you revive Ahrima after discarding it, and if you have Diabolos in hand or the grave, you can summon it right there by tributing Ahrima to draw rather than search (the latter options requires another monster as tribute). Alternatively, it can be used to grab a monster in the opponent's graveyard to be used as the Diabolos-summoning viable tribute target without costing the once-per-turn lair tribute, which can in turn be used for Diabolos's effect.


• Lilith, Lady of Lament also works as a one-card means to summon Diabolos, but will cost you your normal summon (or MR if you somehow have her in the graveyard). She allows you grab traps like the viruses to make the big disruption play. The main issues with her include the telegraphed trap play of course, the fact that the effect is unusable once you are down to 2 normal traps in the deck, and that the one-card-play really denies you the ability to use the effect on your opponent's turn as a uninterruptible monster removal (In this deck Lilith, the viruses, and Dark Spirit Art-Greed are the only effects that allow you to do that on either turn).


• Armageddon Knight works as another Foolish Burial, but costs you your normal summon. In that case, you would summon Diabolos via Duke tributing Armageddon.

Plan B: Stall it out

Given the strong presence of traps that are used in part to provide to Lilith with targets, even without the right offensive pieces, we can try to delay the game a bit so that we can get them. Our main stall monster is  Vijam, the Cubic Seed . It provides a set-able wall that will cost your opponent their monster's effects (and then you can just re-summon it from the spell and trap zone) or will continue to act as a non-battle destroy-able wall until your turn. Again this fits the theme of simply stalling the game out, but since we just set this, we can potentially avoid letting the opponent know what we are actually using until turn #4 (assuming we went second. Furthermore, it works as a target for Recurring Nightmare , which gives a +1 if and only if we have 2 or more monsters with 0 defense in the grave as targets (both Lilith and more importantly Ahrima fit that requirement) .

• Scapeghost is also used as a stall card that more importantly advances our game state going into our next turn. 4x lvl 1 0/0 Zombie-type, Black Sheep tokens provides ample shielding against non-piercing boards. If they actually survive, we can use them to make Link Spiders, which we can turn around and use to make effect monster requiring links like Decode Talker. This card is much better if we have Linkuriboh available, although that is definitely will not be a budget friendly card until the next starter deck comes out in mid-July 2018. This could be used to make Firewall Dragon (again not the most cheap card at the moment, will come down assuming it gets reprinted as a tin promo) as well (although more often than not that one comes out from Lair's tokens).


• Dark Hole/Raigeki (budget permitting) work(s) as a quick way(s) to clear a board(s), although both have a tendency to be ineffective if we actually have the tribute-engine online.


• Mirror Force is of course the classic answer to attack defense. Can work well in conjunction with Scapeghost to keep it alive in order to flip it up and synchro-summon off it rather than just link-out with tokens.

Notes on the Other Cards Used

• Malefic Stardust Dragon: Theoretically protects Lair of Darkness, but more often than not it is used as a stepping-stool for getting Diabolos out by being a valid tribute for it's summoning effect. Also can be used to make a rank 8 xyz with Diabolos like Hieratic Sun Dragon Overlord of Heliopolis .


• Diabolos, King of the Abyss: The original version of Diabolos is costly to summon at two tributes (with no special summoning potential), but it will always generate valid tributes for darkest's summoning effect (because Lair does not give you tributes for tribute summons, it only gives the opponent tribute for effects). This one will not win a game for you, but it is a way to clinch a win out by selectively managing the opponent's draw phase while under the effects of a virus. Would be a lot better if it was 3k attack and level 8.


• Soul Release: I generally like to include this card because it allows for grave managing offensively (banishing anything the opponent has in the grave that could be a target for something) or defensively (taking out grave-originating effects). Practically mandatory if GGV was used to take out any upside your opponent got out of it.


• Dark Spirit Art - Greed : Allows for a really dirty way to abuse the viruses. All but GGV gives you hand information, meaning you know whether or not the opponent could even negate it, but with lair active it becomes even more nasty. I started using this instead of Share the Pain since it could be a Lilith target and I started to feel that Allure of Darkness tended to hurt me more than it helped, given I have no way of interacting with banished cards in this deck.


• The Transmigration Prophecy : This one came out of a project to try to find a way to recycle destroyed lairs, as well as find more normal traps that were actually worth running (namely stuff other than battle traps and other situational traps that are hurt from the telegraphing so much). This ends up working somewhat like trap version of Soul Release, but I can also use it to recycle key cards that I have used up, namely lairs and particularly EEV.


• Vampire Sucker Actually have not summoned this even once yet (in general I do not use the extra deck much with this). Mainly have it in there is as a highly situational means to draw possibly two cards off Scapeghost, one from summoning an opponent's monster by Sucker's effect, and then drawing for doing so, and then another from Formula Synchron. I could then tribute Sucker and the monster I summoned with sucker (by her own effect, not lair) into a Diabolos, darkest or original.

Diagnostic Manual Mk5

In order of severity.

• Eradicator Epidemic Virus
  
  
  
  • Symptoms: Loss of Spell or Trap Capacities from the field or by drawing.
  
  
  • Notes: There is a reason this is the only one that is limited. Many decks require spell cards as either ways to draw or search for pieces of their combos, and in other cases killing traps simply clears the way for Diabolos to beat them into submission. Definitely the most common target for Lilith other than the triple bottomless search. Pretty easy to use with how common monsters with 2.5k+ attack are.
  
  
  
  


• Full Force Virus
  
  
  
  • Symptoms: Loss of non-defensible (1500 or less) 'cells'. Can not take hold in non-defensive cells (Link monsters)
  
  
  • Notes: At first I was skeptical of using this card, but given how often Duke ended up sitting on the field (requires a 2k defense tribute like duke), it made for a good inclusion. This one actually manages to get a lot of monsters that people still use given how aggressive the game has become.
  
  
  
  


• Deck Destruction Virus
  
  
  
  • Symptoms: Victimizes weak individuals (1500 or less atk), but effective against non-defensive hosts as well.
  
  
  • Notes: It is almost never an issue to find a target this (once Lair is up), but it really misses a lot of targets now. There are decks that use basically no monsters whatsoever that would be hit by this (Evilswarm, a deck where I used this as well, being one of them if the build does not run Evilswarm Obliviwisp). The one thing it can do well is of course is hit a bunch of weaker link monsters.
  
  
  
  


• Grinning Grace Virus
  
  
  
  • Symptoms: Targets newborns (newly drawn monsters).
  
  
  • Notes: This one requires a 2000+ attack tribute (maxing out at 3000), to actually get the desired effect, but always forces the selective loss of monsters from the opponent's hand or deck for every 500 atk of the tributed monster. Thankfully it does prevent the use of the destroyed cards for the turn of their loss, which will actually hurt deck like burning abyss where the effects are on the transfer to the grave and not selectively triggered after-the-fact (but many of those cards already had restrictions on using their grave effects the same turn), but it allows for easy grave-loading. Currently this runs 0 in the main deck as it seemed to be accomplishing little, plus it does nothing for the field situation or the hand.
  
  
  
  


• Crush Card Virus
  
  
  
  • Symptoms: Wide-spread controllable outbreaks (kills anything over 1500 attack, but with a lot of penalizes attached)
  
  
  • Notes: This one got errated hard. It has the deck destruction effect like GGV, but it is optional and basically any deck can find something over 1500 atk that it would like to be in the graveyard. The main thing it does do is wreck the heck out of field, but your opponent is under total LP damage protection for the next 2 turns, so you flat out can not win the game until they have had a chance to respond. Basically the only reason to run this at this point is for The Fang of Critias into Doom Virus Dragon play, but there is no good way to get the Fang in a timely manner.