Viruses, Gotta Infect 'em All

Scary, isn't it?

Viruses, from Crush Card Virus, the forbidden one, to Deck Devastation Virus and Epidemic Eradicator Virus, they're all scary traps that deplete the opponent's hand and field and disrupts their game.
Crush Card Virus, aka. CCV, is the most known one: it's banned for a reason, just tribute a random Sangan and you can kill all of your opponent's plays by destroying all the monsters with 1500 or more ATK from their field and hand and for three turn, other than checking pretty much all of the cards they have and the ones they draw for the remaining three turns.
Deck Devastation Virus, DDV, is the easier to activate as of now, since it requires only a 2000 ATK or more DARK monsters, compared to the 2500 or more for Epidemic and CCV that's forbidden by the banlist. Destroying all of the monsters with less than 1500 ATK is a great effect, since Wind-Ups die to it, and lots of other decks from the past banlist do too. Sadly, this new meta isn't that reliant on little monsters. Sure, you can kill Diva, Infantry, Marksman, Linde (before they summon her) and likes, it does kill Chicken, Spirit and Panther for LV3 Fire Fists and it destroys Spellbook Magician of Prophecy, but still all of these decks have great search power and can retrieve from the grave with ease and doing so swiftly avoids DDVs effect.
Epidemic Eradicator Virus, aka. EEV, is the hardest one to activate (not considering that CCV is on the banlist), but it has a great effect. Tributing a 2500 or more ATK monster to choose between Spells or Traps for the opponent to keep under control is awesome. Spellbooks totally die to this, Dark Worlds too, Raven and Trance Archfiend aside, not considering that Fire Fists lose all of their tenkis and Tensus and so on. What's more, being able to play this card without heavy minusing yourself is an awesome thing because you can destroy all of the staples, no matter the deck, and if the deck you're against to isn't spell/trap reliant, you can side this card out.

Now you'll be thinking "Well? We all know the Viruses, what's the point in explaining them?", right?
In these days I'm experimenting a concept I had in my mind for quite a while, but lacked some pieces for working correctly in the past. Thanks to T.G. Striker, from Pojo, I discovered how to work with it and it's working indeed.
Remember my Toolbox post? I basically said that Extra Deck's Toolbox is awesome because you can have whatever you need without waiting to draw into it, just into two materials to go into it. Same here: considering you'll have to summon a 2000 or more ATK DARK monster for DDV, you'll have to draw into 2 specific cards, at least, one is DDV itself, the other one is the monster. However, since it has an high ATK, it is likely that that monster will have to tribute a monster or two, or activate a specific card or anything really. To fix this, we'll just have to use the Extra Deck. If we were to make a list of all of the valid targets for DDV or EEV that reside in the extra, it would be extremely big, about 60 cards (if you want to see them, open DN and search there). Considering only the XYZs, though, the list would shrink to 17 cards:
2000 ATK or more.
Black Ray Lancer
Evilswarm Bahamut
Evilswarm Thanatos
King Feral Imp
Magi Magi ☆ Magician Gal
Number 50: Blackship of Corn
Queen Dragun Djinn
Shark Fortress
2500 ATK or more:
Adreus, Keeper of Armageddon
Chaos Xyz: Dark Fairy Cheer Girl
Evilswarm Ophion
Evilswarm Ouroboros
Hierophant of Prophecy
Number 11: Big Eye
Number 22: Zombiestein
Number 40: Gimmick Puppet of Strings
Number 88: Gimmick Puppet - Destiny Leo
(incoming Number 66: Master Key Beetle)

As you can see, many of them are generic or easy to summon. For DDV, Blackship of Corn is a godsend, since it is already a staple and totally generic. If we want to specify, then, every deck that has access to R4s is DDV-ready. As for EEV, consider that Adreus is generic, Big Eye is too, and even Number 40 (number 88 is hard to summon, not counting him). As of that, every deck that can summon R5s, 7 and 8 is EEV-ready.

Still, using DDV this way is, a -2 for the materials of the Xyz, then a +1 for the summon, then a -1 for the tribute and a -1 for DDV itself. On you, this is a -3. EEV is another thing, summoning 2 lv5, 7 or 8 monsters usually wastes lots of resources, making it a still worse card in terms of costs, excluding broken decks and easy plays, namely elemental dragons.
What can we do for this? We need something that makes this a 0, or at maximum a -1. Other than using the summoned monster's effect first, what else can we do? Reborning it is a great thing. Let's say you have an Adreus in the grave because you used it before, just Call of the haunted would make a great EEV target, but there's more to this.

Reborn for XYZs

Xyz Reborn is a +0 upon summon, however, considering it attaches itself to the summoned monster, you should be able to use that monster's effect and plus (corn destroys an opponent's monster for a +1, Big Eye steals one making it, theorically, a +2, Adreus destroys a card for a +1), then you can tribute it for virus.

We've come to the engine itself, finally. I've been testing this for the past 2/3 days, and it looks good:
0/2 Xyz Reborn
0-2 EEV
1/2 DDV

Usually it is 2-2-1 where I can summon R5/7/8 or 0-0-2 where I can summon R4.
The engine is even entirely side-able so that you can side as much hate as you want against Spellbook, DW, or whatever.

Try to splash it, you'll like it. If you need some ideas:
Gem-Knights, preferably sided since it generates lots of minuses. You can go into Prismaura and Citrine and then Big Eye.
Elemental Dragon, easy enough to figure why, you can tribute Big Eye and LaDD. Either sided or mained it's ok.
Constellars, Adreus is the way. It's ok either if mained or sided.
Umbral, they have Master Key Beetle, awesome EEV target. I'd say mained, but we'll have to wait their release on DN/YGOPro.

The possibilities are really lots and lots, you'll just have to try them.

See Ya

Naturia Beast, Relevance in the Meta

1 EARTH Tuner + 1 or more non-Tuner EARTH monsters
During either player's turn, when a Spell Card is activated: You can send the top 2 cards of your Deck to the Graveyard; negate the activation, and if you do, destroy it. This card must be face-up on the field to activate and to resolve this effect.

Naturia Beast, one of the Naturia Synchros Trio (not considering Leodrake since he hasn't a negation effect), arguably the best among them. I named this card lots of times in the past, from Iron Chains, to Madolches, from Beast Synchro, to Karakuris and other lots of thingies. I noticed the strength of Karakuris, mainly, in this meta, with that Naturia Beast, but someone (Desmond Johnson) managed to show it to the world. I must admit that his build works a lot better than the one I was trying for this meta. It had pretty much the same basics, only that I played 3 decrees for the sake of drawing them as early as possible and go into a lock with Naturia Beast. However, they were quite the DDs, but sometimes they were way too useful, I'm still confused about them. Another thing Desmond noticed and I didn't was that Solar Wind Jammer could SS itself without monsters on the opponent's side.
Back on today's topic, Naturia Beast. Well, you should know by now what the next meta is going to look like, right? Mermails and Fire Fists till the release of Spellbook Judgment Day, where they'll become part of the meta, then, once HA7 is released, Evilswarms will be the main antimeta choice.
Beast is unstable in this meta, Spellbooks dies to it (aside Junon+3 Spellbooks, for that exact reason you should aim to the win as fast as possible), Fire Fists will be slowed down till they have a beater (tenken+something, reason why I used to play 3 decrees in my build), Evilswarms don't have access to Pandemic, but they can run over Beast with just Ophion (Decree is helpful here, too) while Mermails aren't really that affected, aside salvage and such, but they can kill beast with ease. For those reason, Naturia Beast is quite controversial.
However, when judging a certain card, you must always consider what type that card is: Infernity Launcher is way more broken than Mirage, even having the same effect, pretty much.
This card is the same thing: it is a synchro, thus it resides in the extra. Considering your extra a toolbox, as I always do, this card can be brought to the table when needed, and not waiting to draw it and being a DD from time to time.
If you are against Mermails, you'd rather go into Stardust than Beast, but against Spellbooks and Fire Fists the latter is awesome and against Evilswarm you'd go into a beater for their Ophion or, if you've got Decree, into Beast to attempt a lock, if they aren't too close to summon Ophion.
The decks that can afford easy summoning of Beast (and possibly barkion) have some potential not only for Beast itself, but even for the synchro ability: if you can summon Beast, you surely can summon Catastor, that's a great card itself, probably Stardust and Scrap and maybe Black Rose. Having that kind of toolbox (considering all of the XYZs, too) is a great arsenal for a player's deck.

I hope some other original deck makes it to the top of some important event, originality is always a good thing. Maybe some will be able to do so via Naturia Beast, who knows.

See Ya