If it’s Normal or Special Summoned, Keeper of Dragon Magic allows you to add 1 “Polymerization” Normal Spell Card or “Fusion” Normal Spell Card from your Deck to your hand by simply discarding 1 card. You can use Keeper’s effect to search Neos Fusion, Miracle Fusion, or even Magicalized Fusion (Dark Cavalry).
During your Main Phase, by revealing 1 Fusion Monster in your Extra Deck, Keeper of Dragon Magic allows you to Special Summon 1 of the Fusion Materials )whose name is specifically listed on it) from your GY, in face-down Defense Position. You can still use that face-down monster (Elemental HERO Neos) as Fusion Material.
The fact that you cannot Special Summon monsters from the Extra Deck, except Fusion Monsters, the turn you activate either of this card's effects don’t really matter since that’s the only type of monsters we intended to Summon anyway.
Use Neos Fusion to Special Summon Elemental HERO Brave Neos from your Extra Deck by sending Elemental HERO Neos and a Level 4 or lower Effect Monster (ideally Bacon Saver or A/D Changer) from your hand, field or Deck to the Graveyard. After this card resolves, you cannot Special Summon monsters for the rest of the turn, so make sure you Special Summon Lava Golem or activate Miracle Fusion before Neos Fusion.
You can banish Neos Fusion from your Graveyard to prevent Elemental HERO Brave Neos or Elemental HERO Neos Knight from being destroyed by battle or card effect.
Elemental HERO Brave Neos gains 100 ATK for each “Neo-Spacian” and “HERO” monster in your Graveyard. If you have at least 1 Elemental HERO Neos in your Graveyard, Brave Neos will be able to get over a Legendary Six Samurai - Shi En, a Darklord Ixchel (in Attack Position), and it will tie with Darklord Nasten.
When Elemental HERO Brave Neos destroys an opponent's monster by battle, it allows you to add 1 Spell/Trap from your Deck to your hand that specifically lists the card “Elemental HERO Neos” in its text. You can use Elemental HERO Brave Neos’s effect to search Neos Fusion or even a Miracle Contact.
Lava Golem is used to remove problematic monsters such as Desperado Barrel Dragon from the board, it can be Special Summoned in Defense Position and then destroyed by Elemental HERO Brave Neos to search another Neos Fusion, and it can even finish off your opponent by itself with its effect. You don’t need Lava Golem? Discard it to search Miracle Fusion, and then use it to Fusion Summon Elemental HERO Nova Master.
This Skill (and World Legacy Clash) will help Elemental HERO Brave Neos deal with high ATK monsters such as Vendread Battlelord, Desperado Barrel Dragon, and Darklord Desire. Thanks to Neos Fusion and Miracle Fusion, it’s fairly easy to get multiple Level 5 or higher monsters on the field and take full advantage of Beatdown.
Switcheroo allows you to shuffle an eventual unwanted Elemental HERO Neos or Bacon Saver back into your Deck for another card (or the exact same one if you’re unlucky). The synergy with Cosmic Cyclone is obviously great, but the addition Keeper of Dragon Magic has given us an alternative way of remedying unfortunate draws while also setting up the Graveyard for Miracle Fusion.