Alright, this list is all about the Subterror Behemoths! Vernusylphs give us the ability to send from the hand, or deck, Subterror Behemoths to the GY, and then reborn an Earth monster! Vernusylphs lock us into only using Earth monster effects for the rest of the turn, which isn't a problem since all of the Subterror monsters are Earth-type. Since we're playing a flip-deck, we need Spell/Traps that flip our mons and other cards to protect those Spell/Traps. The Extra Deck is not finalized, but it is a rough assembly of cards that benefit our strategy.
This deck is based off of suggestions and information from the Subterror Discord, most notably from user ThePurplePancake. Many thanks to you, this list would not be nearly as competent without your help!
We are playing 3 Lord of the Heavenly Prison, our main way to protect our backrow and set cards. What we grab off of the summon of LotHP depends, but will usually be The Hidden City (if we haven't found it already), Sol and Luna (for removal), or Pot of Desires for draw power. We are playing 1 Nibiru, searchable off of Gallant Granite. 1 apiece of Subterror Behemoths Voltelluric, Umastryx, and Stygokraken. If we end on a board without Guru or fiendess, we want Umastryx. Otherwise, it depends on our opponent's deck which Behemoth we want to search. We are on 1 Guru and 3 Fiendess. Normally Fiendess is best at 2 or 1, but in this list we can normal summon Fiendess and use their effect to reborn a Behemoth. FOr hand traps, we are playing 2 Ash Blossom, 2 Ghost Ogre, 2 D.D. Crow, and 2 Infinite Impermanence. We are on 3 Sol and Luna and 3 Final Battle for our flip Spell/Traps. The Vernusylphs are 3 Awakening Forests (our main way of searching Behemoths), 3 Fourishing Hills (can search any other Vernusylph card), 2 Thawing Mountains (draws us a card), 1 Vera, the Vernusylph Goddess, 1 Corolla (makes our Subterror mons Vernusylphs, benefitting from Flourishing Hill's protection), and 1 Flower Buds (decent removal spell, resets the board). I'm currently on 1 Planet Pathfinder, as finding The Hidden City is vital to most of our plays, but I may cut this, and other cards, as I play-test more with this list.
The primary combo with this deck is started by opening The Hidden City and any Vernusylph. One of the optimal lines is Hidden CIty + Awakening Forests. Play the Hidden City, search and set Guru, use Hidden City to flip Guru and search Fiendess. Activate Awakening Forests to discard itself and Fiendess and send a Behemoth of your choice from the extra-deck to the GY. If you have a Sol+Luna or a Final Battle in hand, use Fiendess to flip-down Guru and revive the Behemoth, and set your Spell/Traps. If you have another Vernusylph and a mosnter in hand, use the Vern to reborn the Behemoth, instead, leaving Guru, Fiendess, and the Behemoth face-up. Opening Fiendess and Awakening Forests/Flourishing Hills is also a strong start. Discard Fiendess for the Vernusylph activation, and send a Behemoth to the GY while reviving Fiendess. If you used Flourishing Hills, search Awakening forests, and use their effect to send the Behemoth. Any Play where you can start with Awakening Forests, you can instead start with Flourishing Hills, as long as you have enough monsters in hand to activate their effects.
I hope this has been an interesting take on Subterrors with the new Vernusylph as support! If you have any questions or ideas for the deck, please leave a comment down below!