You can learn more about what a deck is meant to have in our Beginner Guide (coming soon)
Their effects cannot be activated when they cannot declare an attack (i.e
Spell Miracle Contact Normal Spell Shuffle into the Deck, from your hand, field, or GY, the Fusion Materials that are mentioned on an "Elemental HERO" Fusion Monster that mentions "Elemental HERO Neos" as material, then Special Summon that Fusion Monster from your Extra Deck, ignoring its Summoning conditions.
If Summoned this way, during each End Phase: You take 1000 damage
SR Super Rare Branded Disciple X SPELL Continuous When a monster effect activated by your opponent resolves, if that opponent's monster has 0 ATK or DEF, and you control a Level 8 or higher Fiend Fusion Monster, you can negate that activated effect
The only real drawback is that you cant activate your own traps either