Heaven Exterminating Bloodline
The black bead was originally the orb of disaster. This is the reason why nobody got their hands on such items because if they do then their life will turn into the worst nightmare ever. If a weaker person finds it, then he will die within a week with misfortune. While a strong person won't even dare to take it, so this bead was decayed in history, and so nobody could find it.
Even if they do find it, then they will bring misfortune in their life. But Fei was different; he got the strongest luck in the universe which was enough to suppress the misfortune of this bead. But the source of the misfortune was something instead of this bead, it is a person or rather bloodline of that person.
From Linger, Fei learned some history about it. Before several eras, to be specific before sixteen eras, in that previous era lived a person named Disaster God. He was the source of all misfortune but he died due to the conspiracy of other gods.