Cosmo Brain is an interesting addition to the game, its effect gives many high Level Normal monsters a way to be Special Summoned directly from the Deck.
This deck focuses on Special Summoning Dark Magician from the hand, Deck or Graveyard, using Cosmo Brain, Ancient Rules, Dark Magic Curtain and Birthright, and then takes advantage of the various support cards we have in the game for the iconic Level 7 Spellcaster to get rid of the opponent’s backrow and/or monsters.
Once per turn, if Legion the Fiend Jester is sent from the field to the Graveyard, you can add a copy of Dark Magician from your Deck or Graveyard to the hand; you can Summon this monster and wait for your opponent to destroy it or you could Tribute it to activate Illusion Magic’s effect, essentially adding three copies of the Level 7 Normal Monster to your hand.
Once you have Dark Magician in your hand, you can Special Summon it with Ancient Rules, which is now available at three copies, or you could discard it to Special Summon Cosmo Brain.
You can Special Summon Cosmo Brain by sending a Dark Magician from your hand or face-up on the field to the Graveyard, Cosmo Brain then gains ATK equals to the Level of the monster you sent x200, which means that, in this case, it will reach 2900 ATK, which is quite respectable.
Once per turn, Cosmo Brain allows you to Tribute an Effect Monster to Special Summon a Normal Monster from your hand or Deck; you can Tribute Legion the Fiend Jester to trigger its effect and add a copy of Dark Magician to your hand or you could just Tribute Cosmo Brain itself and Special Summon a Dark Magician from the Deck.
When Magician’s Rod is Normal Summoned, you can add a Spell/Trap that lists “Dark Magician” in its text from your Deck to the hand; essentially this card can search Dark Magic Curtain, Dark Magic Attack, Illusion Magic and Thousand Knives, if you decide to run it.
Once per turn, if you activate a Spell/Trap Card or effect, you can add Magician’s Rod from the Graveyard back to the hand by tributing a Spellcaster monster; ideally you want to Tribute Legion the Fiend Jester with this effect.
Dark Magic Curtain allows you to Special Summon a Dark Magician directly from the Deck by paying half your Life Points and it also brings you range for Master of Magicians right away; keep in mind that you can’t Summon other monsters the turn you activate this card, you can only Set a monster, so you can’t search Dark Magic Curtain with Magician’s Rod and then activate it.
With the addition of Cosmo Brain, having a Dark Magician on the field is even less difficult, so activating this Spell Card and destroying all Spell & Trap Cards your opponent controls is fairly easy; Dark Magic Attack is very effective against decks like Amazoness that like to hide behind their backrow and it’s pretty much necessary seeing how popular this deck has become.
After you have sent Dark Magician to the Graveyard to Special Summon Cosmo Brain or the monster has been simply destroyed by a Treacherous Trap Hole, you can Special Summon it with Birthright; this Continuous Trap can be used to prevent early OTKs.
This deck doesn’t run cards like Cosmic Cyclone, so activating this Skill is not exactly easy; Thousand Knives and Dark Magic Attack are both pretty good cards, especially since they are added to the hand from outside the Deck, and Dark Magic Expanded has also synergy with Cosmo Brain, the other high Level Spellcaster of the deck.
Compared to the one that features Silent Magician, this version is more consistent, but it does lack that “once per turn” protection the Level 4 Spellcaster can provide and its ability to float into a 3500 ATK monster after being destroyed; on the bright side, the recent further rise in popularity Amazoness decks have seen has definitely made Silent Magician less viable.
Going first generally puts this deck, like many others, at a disadvantage, Sphere Kuriboh, Paleozoic Canadia and Treacherous Trap Hole are all cards that can be considered to solve this issue.