Is it possible that Blizzard hid a hint on Diablo 4 in a box with a gifts on BlizzCon 2016? It is very likely. Meanwhile, one of the known YouTuber and streamers Kripparian, released the video online in which we can see these gifts:
As you probably know, buying such a box is possible, after purchasing a virtual ticket to BlizzCon, or participation in the event - which involves undoubtedly huge costs.
Therefore we explain what's going on in the plot of Diablo 4. Now, in a box with gifts is a bag of dices, like in D&D - D20, D8, D6, D4. Does D4 not associate with Diablo 4? Yes, of course it does!