I reaffirm this card would be bad in a ghostmare deck. The main strength of such decks is making the opponent draw as little new cards from their deck as possible, through making them miss draws and reversing their creatures. Making your opponent draw 2 new cards goes against you.
Even if playing the shard would fill the opponent's hand (note that discard only happens at end of one's turn), in that case you would have neutral card advantage, yes, but you will exchange 1 card for another such as Precognition does, and for that prupose Precognition is better.
Because:
- costs less.
- lets you see your opponent's hand and next draw.
- you will not give your opponent card advantage if their hand is not almost full.
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Where will this card be really useful:
-Any deck, versus AIs with double draw. Filling its hand or almost, makes it draw 1/2 less cards.
-Decks formed of low quanta cost cards/rush decks. While you may play all the 2/3 cards you draw the turn you use the shard, your opponent might have to wait for quanta production. Thus it might not be as good for your opponent as is for you. (albeit the card comes together with the nova/snova nerf)
-OTK decks. Where you want to draw your whole deck, although while playing those decks, you will have to keep in your hand the cards you are going to use for the final turn show, wich might ruin your multidraw ability.
-Decks whose winning strategy is deckout. While not very popular at the moment, they might become popular with the addition of this shard. Imagine against a 30 card deck, making it draw 12/18 cards, you only have to stall during 11/5(!!) turns.
-SoSa decks. Your opponent is not likely to do much with the extra cards when you are under the inverted damage effect, while you may need to draw more SoSas to keep you alive.
(note that english is not my native language, also that this post contains more opinions than facts)