Stardust Acceleration hasn’t done a particularly great job when it comes to introducing the new mechanic into the game as summoning a Synchro Monster still seems to take too many resources and to mostly not be worth it in the end, but there is one good thing that did come from this Main BOX: Genex Undine. This monster is a great card to add to the standard Sea Stealth Attack Deck as it can improve it by making it more consistent with its effect.
Building an actual Genex Deck is nearly impossible right now, but that's not just because of the limited amount of cards we have available, it’s because most of the monsters that are part of this archetype have terrible effects and/or no synergy with the others.
This Deck focuses on getting Citadel Whale on the field with the help of Genex Undine and protecting it with Sea Stealth Attack; Hydro Genex is used as a secondary Boss Monster as it can also benefit from the Continuous Trap.
When Genex Undine is Normal Summoned, you can send a WATER monster from your Deck to the Graveyard to then add a Genex Controller from the Deck to your hand.
As you can imagine, there are many ways to take advantage of this effect: you can select Atlantean Marksman or Atlantean Heavy Infantry to destroy a face-down or a face-up card on the opponent’s side of the field or you could send to the Graveyard a card like Treeborn Frog, Dragon Ice or Citadel Whale, which can all then be Special Summoned from there.
Since Genex Undine’s effect triggers when it is Normal Summoned, both Paleozoic Canadia and Floodgate Trap Hole will not prevent its activation, but, at the same time, you will not be able to activate the effect if you Special Summon the monster with Hammer Shark’s effect.
When it’s Normal or Special Summoned, Beautunaful Princess can be banished in order to Special Summon Hammer Shark of Fishborg Planter from the Deck.
Hammer Shark is a very important card in this deck because its effect allows you to, once per turn, Special Summon a Level 3 or lower WATER monster from your hand–it’s the easiest way to get two WATER monsters on the field to tribute for Citadel Whale.
If Citadel Whale is in your hand or in your Graveyard, you Special Summon it by tributing two WATER monsters on the field–this action does trigger the effects of Atlantean monsters like Marksman and Heavy Infantry–and, when Citadel Whale is Special Summoned, you can set a Sea Stealth Attack from your Deck.
Citadel Whale offers some form of protection for itself and other WATER monsters: it can negate a card of effect that targets one WATER on your side of the field, meaning Treacherous Trap Hole would not be among the cards that could be negated, but it can only be used once per turn.
Sea Stealth Attack adds another layer of protection to your main monster, allowing you to banish one of your WATER monsters once per turn in order to make your face-up Spell/Trap Cards immune to destruction effects; this first part of Sea Stealth Attack’s effect can be activated in response to the activation of a card that targets Citadel Whale to prevent it from being destroyed or banished.
The second part of the effect of the Continuous Trap protect all of your Level 5 or higher WATER monsters from destruction by battle, destroying before the Damage Step any monster they battle with; this effect can get around Amazoness Onslaught, Amazoness Swords Woman and many other cards.
Paleozoic Canadia is a great form of protection against most of the current meta decks nad it can also be used as tribute for Citadel Whale after Special Summoning it from the Graveyard.
Hydro Genex acts as a secondary Boss Monster for the deck, it’s a Level 6 monster, you can Special Summon it by using Genex Undine and Genex Controller; Hydro Genex’s effect has also poor synergy with Sea Stealth Attack, which is arguably the best support card for Level 5 or higher WATER monster.
In order to activate Genex Undine’s effect, you must have at least one copy of Genex Controller in your Deck; Switcheroo offers the possibility of shuffling the Level 3 Tuner back into the Deck after you unluckily draw it or simply after you add it to the hand.
Wiz, Sage Fur Hire can prevent you from activating Sea Stealth Attack, but getting rid of this monster is quite easy with the combination of Genex Undine and Heavy Infantry; if you Special Summon Citadel Whale by tributing Heavy Infantry, it goes without saying that Wiz should be your primary target for the destruction effect.
Fur Hires usually rely on Recon and Hey, Trunade! to get rid of the opponent’s backrow, but Sea Stealth Attack provides protection against them; considering its own effect and Sea Stealth Attack’s, you can prevent Citadel Whale from being destroyed twice per turn.
If the deck is late to set up the board, Fur Hires can easily overpower it and end the game, otherwise it shouldn’t be too difficult to deal with them, unless Donpa, Marksman Fur Hire destroy Umi on the first turn before you have the chance to even set Sea Stealth Attack.
A “once per turn” removal effect really doesn’t sound that threatening and no matter how big these monsters can get under Vampire Kingdom, Sea Stealth Attack will still get rid of them if the try to attack into Citadel Whale. Problems may arise if the opponent goes first and manages to get rid of the Field Spell by summoning Vampire Grace while having the Field Spell active.
Sea Stealth Attack can protect Citadel Whale from being destroyed by Yubel - Terror Incarnate’s effect by banishing it and this would also protect both Umi and the Continuous Trap from being destroyed by Sacred Phoenix of Nephthys;
The only problem in this case is that you would likely leave an empty field with nothing between your opponent’s monsters and your Life Points. Assuming Terror Incarnate is on the field, you can first destroy it with Genex Undine by sending Heavy Infantry to the Graveyard and then use Sea Stealth Attack to destroy Yubel - The Ultimate Nightmare, getting out of the lockdown.
Sea Stealth Attack’s effect does not protect your face-up Spell/Trap Cards from being banished, which means that Cosmic Cyclone, a quite common card in Masked HERO decks, is a big threat. Without Umi or Sea Stealth Attack, Masked HERO Anki can get over Citadel Whale, but you still have Paleozoic Canadia to protect it.
This deck runs no Spell Cards, so Silent Magician’s “once per turn” negation won’t affect it; Spellbook of Fate is the biggest threat in this matchup as it can banish Sea Stealth Attack or Umi without you being able to do anything to protect them.
The strategy in this case should be to use Paleozoic Canadia to flip the opponent’s Spellcaster-Type monsters face-down, preventing the activation of the Spellbook cards; Silent Magician and Silent Magician LV8 are not a problem as Sea Stealth Attack can easily deal with them.