What if I told you that there's a single card that can almost completely shut most meta decks down? Numen erat Testudo is the hero we need: its effect prevents players from Special Summoning monsters with 1800 or less, meaning every Fur Hire excpept for the now limited Dyna, Hero Fur Hire and every Amazoness except for Amazoness Queen; A Legendary Ocean allows you to Normal Summon Level 5 WATER monsters and Sea Stealth Attack makes up for Testudo's naturally low stats, providing protection.
Due to the fact that Numen Erat Testudo is a Level 5 monster, it can't be Normal Summoned naturally, but you can utilize A Legendary Ocean to reduce its level by 1 or Soul Exchange in order to Tribute an opponent's monster.
Your primary focus should be getting this monster out as soon as possible and then protect it with your Trap Cards.
Since A Legendary Ocean is treated as "Umi", you can use it to activate Sea Stealth Attack. Its effect reduces the Level of all WATER monsters in both players' hands and on the field by 1, making it possible to Normal Summon Numen Erat Testudo and Deepsea Warrior.
This Field Spell is extremely important, so Warrior of Atlantis' ability to add it from the deck to the hand is very helpful.
This monster is unaffected by Spell Cards while "Umi" is on the field, which prevents it from being switched into Defense Position by Enemy Controller, Destroyed by Super Rush Headlong or banished by Spellbook of Fate.
As long as you have A Legendary Ocean ("Umi") on the field, The Legendary Fisherman can also not be target for an attack, forcing the opponent to attack you directly and allowing you to activate Drowning Mirror Force.
This Trap Card makes the matchup against Masked HEROes better: Sea Stealth Attack and Legendary Fisherman force the opponent to attack directly, making it possible to activate this card even if you don't have an empty field. Drowning Mirror Force can shuffle back into the deck all Attack Position monsters on the opponent's side of the field, it can be incredibly devastating.
None of the monsters in this deck sport particularly high stats, but the majority can take advantage of this Continuous Trap in order to protect themselves from anything that could naturally get over them.
Once per turn, you can banish one of your monsters in order to protect them from cards like Treacherous Trap Hole or Spellbook of Fate or even to restore their original ATK after your opponent has reduced it with Wall of Disruption.
With the correct ration, this Skill can guarantee a starting hand with at least a Monster, a Spell and a Trap Card, considerably increasing the consistency of the deck.
Trap Layer is similar to Balance it's used to increase the chance of starting with Sea Stealth Attack, but you do need to run at least 5 Trap Card with different names in order for it to have an effect.
Once Testudo is on the field, the only monster that can be Special Summoned by the opponent would be Dyna, Hero Fur Hire: Beat, Bladesman Fur Hire can't search it from the deck, Donpa, Marksman Fur Hire and Recon, Scout Fur Hire can't activate their removal effects and Wiz, Sage Fur Hire can only be Tribute Summoned; for once going first against Fur Hires is not a death sentence.
Amazoness Princess can't Special Summon anything from the deck except for Amazoness Queen and neither Amazoness Onslaught nor Amazoness Willpower can target anything else with their effect; Sea Stealth Attack's removal effect activates before Onslaught's, leading to an almost complete lockdown.
Paleozoic Canadia and Treacherous Trap Hole are the main threats in this matchup as they can get rid of Numen Erat Testudo.
Before the introduction of drowning Mirror Force this was one of the worst matchups: Numen Erat Testudo doesn't prevent any of the Extra Deck monsters from being Special Summoned and Cosmic Cyclone can get rid of Sea Stealth Attack; Masked HEROes are not an easy opponent, but facing them doesn't necessarily mean you are going to lose.
While Spellbook of Fate can still be a problem, your opponent will have to banish Testudo if he intends on Special Summoning Silent Magician. Overall Silent Spellbook is not too difficult to face with this deck.