If you've already beaten the "final" black boss and you don't get the hard badge, here's why: That's not the final boss. You have to complete one more quest, which is located in the north alliance camp near the red castle for those who had chosen the alliance and in the east shadow runner's camp near the red castle.
The real final boss is on the north-west, between the two rivers. You'll probably need around lvl 35 to beat him.
Hint: Just separate the colours individuale and perform the dices one by one, and note that in each dice there has to be three pairs, a 6-1, a 5-2 and a 4-3. When you really notice that, the game becomes easy.