The 21st Main Box Cybernetic Rebellion is bringing exactly Mermails have been looking for since their introduction in Duel Links: a Turn 1 play. Mermail Abysslinde and Abyss-sphere are two incredible cards that allow you to Special Summon any “Mermail” monster directly from your Deck, giving you direct access to anything you need.
Use Abyss-sphere to Special Summon Mermail Abysslinde. If Abyss-sphere leaves the field, Abysslinde will be destroyed and it will allow you to Special Summon a “Mermail” monster from your Deck. Even if nothing happens to Abyss-sphere, during the next End Phase of your opponent’s turn after its activation, the Continuous Trap will destroy itself.
Keep in mind that, if your opponent responds to the activation of Abyss-sphere by activating Cosmic Cyclone, banishing the Continuous Trap, you don’t get to Special Summon any monster.
You can use Mermail Abysslinde’s effect to Special Summon Mermail Abysspike and then use Abysspike’s effect to add a Level 3 WATER monster from your Deck to your hand.
Keep in mind that, if you target a face-up “Subterror” monster and your opponent response by activating Subterror Final Battle and changing that monster to face-down Defense Position, the monster will not be destroyed because it’s not a suitable target anymore.
Keep in mind that, if you target a face-down Spell/Trap Card and your opponent activates it in response, the card will not be destroyed because it’s not a suitable target anymore.
You can just Normal Summon Mermail Abysspike, discard Abyssgunde, Special Summon Mermail Abyssmegalo from your Graveyard and then utilize Abysspike to activate its effect.
If you want the monster Special Summoned by Abyss-sphere to stay on the field, you can activate it during your opponent’s End Phase.
You could also use the Continuous Trap to Special Summon Mermail Abyssmegalo or Mermail Abyssteus, but you wouldn’t get much value out of them since even Dragon Spirit of White and Legendary Six Samurai - Shi En are able to get over them without Beatdown! or The Tie that Binds. If you’re sure your opponent is not going to be able to remove it from the field, you can use Abysslinde’s effect to Special Summon Mermail Abyssmegalo directly from your Deck. You will not get to search an “Abyss-” Spell/Trap Card if you don’t Special Summon Abyssmegalo via its own effect, but you’re still getting access to your main monster with relative ease.
You can Special Summon Mermail Abyssmegalo from your hand by discarding two WATER monsters. By discarding Atlantean Marksman, Heavy Infantry or Mermail Abyssgunde, you can get back some value from the resources you’ve invested to Summon Abyssmegalo.
When it’s Special Summoned by its own effect, Mermail Abyssmegalo allows you to add an “Abyss-” Spell/Trap Card from your Deck to your hand.
Alternatively, you can use Abyssmegalo’s effect to search Abyss-sphere, which I’ve already talked about.
Unlike Abyssmegalo, Abyssteus requires you to discard only one WATER monster in order to be Summoned and, to make it even more cost-efficient, it also allows you to add a Level 4 or lower “Mermail” monster from your Deck to your hand when it’s Summoned this way.
This Skill will prevent your opponent from banishing Neos Fusion from their Graveyard to prevent their Elemental HERO Brave Neos from being destroyed by Heavy Infantry’s effect. Secret Six Samurai - Fuma will be able to protect Legendary Six Samurai - Shi En, Subterror Nemesis Warrior will not be able to Special Summon Subterror Behemoth Umastryx from the Graveyard and Diamond Core of Koa'ki Meiru will not be able to save Koa'ki Meiru Maximus, Koa'ki Meiru Urnight and Koa'ki Meiru Ice from their own effects.
If you run Abyssmegalo, Abyssteus and Abyssleed, this Skill can guarantee you one of them in your opening hand, which is fantastic if you’re going 2nd.
Abyssmegalo and Abyssteus have a pretty lackluster ATK, so, even if you’re not going to be able to get them on the field together that often, it’s nice to have a way of getting over monsters like Dragon Spirit of White and Shi En without having to rely on an Equip Spell, which can be negated or banished. Ideally, you would get rid of your opponent’s monsters via Heavy Infantry’s effect and then OTK them, but that’s not always going to be possible.