Infernoid Subterror

The ideal first turn play is opening with Hidden City and Void Vanishment, but starting with just one of these cards is often enough.

A "brief" description of the card line-up;

Monsters

Infernoid Onuncu x2: Dark Hole and backrow negate, two to keep Imagination as a useful card after sending one with Decatron.
Infernoid Devyaty x2: Heavy Storm and monster negate, same logic as Onuncu.
Infernoid Seitsemas x1: Very good removal effect on battle phase, summonable with one Decatron using Feast, and quick effect DD Crow.
Infernoid Sjette x1: Not as good as Seitsemas, but can be summoned with two Decatrons using Feast, and also quick effect DD Crow.
Infernoid Patrulea x1: Spell destruction, and DD Crow on the opponent's turn. Can be sided out for another Harmadik against monster-heavy decks.
Infernoid Harmadik x1: Monster destruction, and DD Crow on the opponent's turn. Can be sided out for another Patrulea against backrow-heavy decks.
Infernoid Decatron x3: Can be any Infernoid, easily searchable with Feast, can be linked off into Almiraj after Normal summoning. All around good boy.

Subterror Behemoth Umastryx x1: Being able to flip to banish is great, and easily doable on the opponent's turn with Final Battle.
Subterror Guru x3: Flips to search the whole archetype, quick effect book of moon while you control another Subterror card, he plays nice with everything. Can also be used to turn Tierra face-down after summon to bring out a big Infernoid from grave.
Subterror Nemesis Archer x1: Phenomenal field removal, being able to shuffle cards back into the deck, and also floats into any Subterror monster.
Subterror Fiendess x3: A handtrap negate at the "cost" of turning a Subterror monster face-down. Easily recyclable from grave. Also brings out Subterrors from grave as a last-ditch rescue move if necessary.

Spells:

The Hidden City x3: Searching, a free flip, and attack prevention that works wonders with Guru's search or Umastryx's banish.
Void Vanishment x3: Search either Feast or Imagination depending on the need, at a negligible cost, and then destroy it for Feast's cost. Its second effect also occasionally comes up. It just needs to be played after Subterror combos.
Void Imagination x2: Resolving this is often game, especially if Guru/City are already on the field. Mill six of choice from deck is beautiful, and then destroy 3 opponent's cards with Elder Entity N'tiss.
Terraforming x1: More Hidden City.
Reasoning x1: A free summon, where excavating doesn't hurt this deck.
Subterror Cave Clash: Makes Guru's Book of Moon effect a quick effect, and gives you free recycling of Subterror cards (usually Fiendess).
Pot of Duality: A blessing going first, saves bricky hands in a deck that doesn't often need its special summon on turn one.

Traps:

Subterror Final Battle x2: Searchable trap that resets itself after use to either buff your monsters, prevent negation, or flip either up or down.
Void Feast x1: As long as you've got another Void card, it's two free negates and a DD Crow on field if this is able to resolve. It helps that the searcher is a continuous spell Void card.
Lost Wind x2: Permanent negate and attack half that recurs from the grave, even if milled by Reasoning.
There Can Be Only One: Sometimes hurts Infernoids, but doesn't prevent Void Feast from resolving, allowing you to fill your grave with up to 5 Infernoids, and doesn't bother Subterrors at all.

Extra Deck: 

Elder Entity N'tiss x3: Just to send to GY with Tierra to destroy opponent's cards.
Infernoid Tierra x3: Big boss that sends cards to GY, running 3 means you can send extra Tierras if you don't need to send 3 N'tiss.
Borreload Dragon x1: Bigger boy
Black Luster Soldier - Soldier of Chaos x1: Big boy, it's also surprisingly easy to summon this boy in a longer game with Decatron after sending almost any Infernoid.
Knightmare Phoenix: Emergency backrow removal
Knightmare Cerberus: Emergency monster removal
Linkuriboh: To link away negated Decatrons or Fiendess in a pinch
Salamangreat Almiraj: To link away normal-summoned Decatrons that are in danger staying on the field.
Predaplant Triphyoverutum: Amazing Super Poly target if your opponent gets three monsters on board, plus isn't blocked by TCBOO.
Starving Venom Fusion Dragon: The more relevant Super Poly target.