I can't tell on his card whether he has a grey dice or black dice for his defense pool. Which is it?

Grey. And adds another grey die to his defense pool in act 2

Decidedly gray . I also saw the die as black because it's darker than other gray die. On the other hand, it's lighter than black die.

Thanks folks.

Funny, i won the GNK and there's no color problem on it

Funny how this question is in the FAQ. I guess they flubbed the printing.