I am a level 46 Myth. I recently realized that as I updated my deck that some of my spells are no longer in the deck, such as the ninja pigs, which was one of my favorites, and the spell where the guy passes gas (sorry if I offended anyone, but can't remember the spells name). Why is this?
These are Treasure Cards, young Wizard, and you must remove them from your old deck and place them in your new deck.
To put Treasure Cards in your new deck, open your Deck by pushing ‘P’.
Once there, click the golden button with cards on it on the top right of the screen. You can now scroll through your treasure cards and place them in your deck by simply clicking on them. Once clicked, they will appear on the left side of the screen and you will be able to draw them in a duel.