I recommend research to help you better understand the meaning of these terms
Regarding EX cards, there's nothing written on them about limiting them to one per deck so this rule from rulebook applies [1] : When you are building a deck, you can have only 4 copies of a card with the same name in it, except for basic Energy cards
The new ability, Vanish , keeps the Giant Cobra protected from actions , or at least ensures mutal destruction
This is the best of the Planeshift charms, which isnt saying an awful lot
Day of the Dragons is pricey in terms of casting cost, but does triple duty here: it almost always upgrades the stats of your creatures, it protects your team from a board wipe, and you can bounce it with something like Blink of an Eye to flash your team back in and trigger their abilities at instant speed
We appreciate that attitude because it's what makes the Cardsphere roll round