I have only one hero as of now boris skullcrusher or something and shadow warrior is not compatible with him but i was still able to buy it. Only when i tried adding that card to my deck i found out...

yes some cards are darkened but not all..i'm playing a warrior deck and i thought it would be cool to have a shadow warrior on my deck, i bought it then found out its incompatible with my deck..had...

I started playing this game 2-3 days ago and it has got me hooked onto it like anything!..been a long time since i got a craze for a TCG like this.
Well, I would like to suggest the game developers...