60-Card Vanquish Soul Snake-Eye Kashtira

I've always loved Vanquish Soul as an archetype, definitely one of the most enjoyable decks I've played in Master Duel. Cool theme and artwork, with a unique playstyle that makes for skillful and interactive matches. Usually it is played alongside a Kashtira engine (a bit weaker and brickier now with only 1 Fenrir), since their cards are really strong individually, providing not only the right attributes with Fenrir/Riseheart (Earth/Fire), but also interruption, board-breaking options, as well as forcing the opponent's interruptions before commiting to your plays. There's however another deck that can also make good use of the Kashtira cards, provide correct attributes (Fire/Dark) and is absurdly powerful - of course I'm talking about none other than Diabellstar Snake-Eye.

As much as I like the standard Snake-Eye deck, after a whole month playing it I feel like I need some variation in my decks. However, it's really hard to keep up in the current meta if you're not using these cards (or countering them with Stun). So, this beautiful abomination of a deck was born, mixing 2 of my favourite archetypes in the game and glued together by cards like Stake Your Soul, Small World or the Kashtiras.

Of course the standard Snake-Eye deck is more consistent, this one has some risk of bricking by drawing the wrong cards of each engine. But it is still very fun to play, both going 1st and setting up all your interactions, or going 2nd and breaking boards by pivoting between engines when your opponent least expects it. It was powerful enough to reach Master V, and could probably reach Master I if I keep grinding (it's still a Snake-Eye deck after all)

Let's take a quick look at each part of the deck:

Vanquish Soul

• The main card here is Vanquish Soul Razen, which on summon searches for another Vanquish Soul monster, and also non-target destroys the monsters on its column, provided you have Fire and Dark in your hand - this can include Snake-Eyes and/or Diabellstar. This card does a lot, being both a way to break boards, bait interaction and also interruption (you can summon it during the opponent's turn with Rock of the Vanquisher or, funnily enough, with Divine Temple of the Snake-Eye or Snake-Eyes Flamberge Dragon after putting it in the backrow with Snake-Eyes Poplar for example).
• Razen is also easily accessible in the deck, being searchable off Reinforcement of the Army, "Infernoble Arms - Durendal" or Small World, also accessible without using your normal summon with Stake your Soul! (by revealing a Snake-Eye in hand for example)
• Supporting Razen, there are a plethora of useful effects, like the extra search of Vanquish Soul Jiaolong, the draw/burn power of Vanquish Soul Heavy Borger, among others. It's worth noting that I cut some cards that are commonly seen in regular Vanquish Soul decks, due to the deck being more focused on Fire/Dark than Earth (like Vanquish Soul Snow Devil, the 2nd copy Vanquish Soul Caesar Valius, etc.)

Kashtira

• Kashtira Fenrir and Kashtira Unicorn are very powerful by themselves, but also serve as a small engine in this deck, working well in both Vanquish Soul and Snake-Eye components of the deck. Free special summons with powerful effects, often leaving them both on the board with a couple extra interruptions from your other engines is enough to win.
• Kashtira Fenrir is an earth monster that can search a fire monster (Kashtira Riseheart). It was more powerful when you were able to play 2 copies, so you could search another earth monster (you still can if you search Scareclaw Kashtira but it's not as good), but it's still very worth playing.
• Kashtira Unicorn has an effect that messes where it should not, and can shut down strategies by itself, and also gets to Fenrir through Kashtiratheosis (locks you into Xyz though! So use only after the main combos are done), or provides access to Kashtira Birth, which can revive a Kashtira after you used it as a material for something, and lets you normal summon Diabellstar the Black Witch (or provide a free card on the field to send to GY) if you really need it.

Snake-Eye

• At this point, these cards need no introduction, so I don't want to get too deep into combos. They have been an absolute menace in all Yu-Gi-Oh formats they are legal, and Master Duel is no exception. Summoning Snake-Eye Ash, search + summon Snake-Eyes Poplar, get the field spell (Divine Temple of the Snake-Eye) or Original Sinful Spoils - Snake-Eye, basically gets you to whatever link monster you want, by using their effects to go through Snake-Eye Oak and Snake-Eyes Flamberge Dragon. The standard line goes for Promethean Princess, Bestower of Flames in GY, I:P Masquerena, Snake-Eyes Flamberge Dragon and Amphibious Swarmship Amblowhale on field, and when you go 2nd you can usually go for game by using Worldsea Dragon Zealantis  
• The package in this deck is smaller than in usual Snake-Eye lists - for example, I'm only playing 2 Snake-Eye Ash instead of 3, since you really want to access it via special summon of Original Sinful Spoils - Snake-Eye, which you get from Diabellstar the Black Witch, or via stuff like One for One. I want to save the normal summon for the Vanquish Soul cards, unless I already have Stake Your Soul in hand. In this deck I also opted to play a copy of Sinful Spoils of Betrayal - Silvera as an alternative card to search.
• Jet Synchron is also serachable within this engine, as well as Kurikara Divincarnate; the first provides the deck with synchro access (and free link material by discarding a card I guess, it could be cut if you prefer to focus on the links or add some more xyz), the second is an amazing board breaker and OTK tool when going 2nd, tributing over the opponent's board after you baited their effects, and is a must have for how powerful it can be.

The tech cards

• A big portion of the deck is dedicated to handtraps, board breakers and consistency cards. You could probably focus on going either 1st or 2nd and adjust the decklist appropriately, but in this best of 1 format I like to be prepared for both.
• You prefer to play tech cards that are Dark/Fire/Earth, for the Vanquish Soul synergy (with Imperm being the exception). For this reason, I cut cards like Nibiru, Veiler or Droll, in favor of the (probably) inferior D.D. Crow, Dinowrestler Pankratops and Alpha, the Master of Beasts. Ghost Belle was a decent option for the Earth slots, but since I don't have that (and I'm low on UR dust) I opted to add some cards which are helpful going 2nd instead. I also considered Retaliating C but it seems too specific. You could also experiment with something like Fantastical Dragon Phantazmay since link summoning is prevalent in this format. Of course playing the cards of the Maxx C/Ash minigame is still necessary, and the Bystials can also be useful (dark attribute, can be used as interruption, or even as a search for Caesar Valius, since it's a Dragon).
• For consistency, you have a variety of options (ROTA, Durendal, Bonfire, One for One, ...) that lead you to one of the engines of the deck. It's also worth noting that Small World can search basically anything in this deck, it might be a -1 initially but it allows you to pivot strategies (D.D. Crow, Pankratops, etc. are all decent bridges) and you will recover the advantage quickly.

So, what's the game plan?

Whatever you want really, depends a lot on your starting hand. Going 1st is great of course, since you get to setup all your interruptions, but going 2nd with this deck is also fine a lot of the time, since a decent hand will have a lot of fuel to play through interruptions and even OTK with Worldsea Dragon Zealantis or Kurikara Divincarnate. You might want to start with the Kashtira cards if you have them, forcing their interaction, and then dropping the Vanquish Soul and/or Snake-Eye combos. When going 2nd, perhaps you wish to bait their board of negates with Kashtira/Vanquish Soul and then special summon Snake-Eye Ash to perform a Snake-Eye combo out of nowwhere; or perhaps you simply prefer to tribute over their whole board with Kurikara Divincarnate.

That's basically it, a fun yet chaotic deck with a lot of fuel to burn bright in this meta. Many aspects can be improved of course, this is all experimental, and I really appreciate suggestions. Now, Stake your Soul and get ready for the fight!