Each Build & Battle Box includes one of four randomly distributed promo cards exclusive to the prerelease format
Here is what I found for how it works Reveille Squad triggers when you are attacked, namely when one or more creatures are declared as attackers against you, which is the first thing that happens in the Declare Attackers step
Protect your Pokmon cards Store and protect your Pokmon card collection with our selection of Ultra Pro products on Amazon : binder and pages, sleeves and top loaders: More Pokmon cards of Unown Unown X 71/132 Uncommon Unown T 67/123 Uncommon Unown S 39/132 Rare Unown K 68/132 Uncommon Unown N 69/132 Uncommon Unown O 70/132 Uncommon Unown F 56/106 Uncommon Unown L 91/106 Common More cards of Ex Unseen Forces expansion Potion 95/115 Common Cyclone Energy 99/115 Uncommon Boost Energy 98/115 Uncommon Metal Energy 97/115 Rare Darkness Energy 96/115 Rare Warp Point 93/115 Uncommon Solid Rage 92/115 Uncommon Warp Energy 100/115 Uncommon
Such an overwhelming majority of the best decks were blue, why not maindeck Red Elemental Blast
It is like Peek and Opt rolled into one
Additionally, while this card may demand a rather steep mana cost, as Demons are rather costly, this spell can be strategically cast once you've built up your board with a few Demons, ideally catching an opponent or two who'd over-committed to the board off guard