It took me some time to finally crack this. If you think this riddle is hard to solve, imagine not having any hints, for the clues I'm giving you nearly solve the riddle, entirely.
"XBT gave birth to his only son, XIC; but the latter will murder his father, in cold blood, and rob him of his crown and all his glory. The wicked son, rising from the sea - who will ruthlessly enslave and rule the world, is marked and will be recognized by all, according to his evil mark and number."
I'll leave it to everyone else to solve this fairly simple riddle. And please don't bother with all the 666 rhetoric, this is gonna require a bit more thinking, but it's there.
In solving this riddle you are likely to find the keys to great fortune; albeit, holding on to that fortune will prove a much greater and painful challenge.
"When shadows descend upon the lands, our divine lords will walk alongside us as equals."
"The Lord of Murder shall perish, but in his doom he shall spawn a score of mortal progeny. Chaos will be sown from their passage."
"The spawn of the Lord of Murder are fated to come into their inheritance through bloodshed and misery. It is the hope of their father that only one shall remain alive to inherit his legacy. I foresee that the children of Bhaal shall kill each other in a bloody massacre."
"During the days of the Avatars, the Lord of Murder will spawn a score of mortal progeny. These offspring will be aligned good and evil, but chaos will flow through them all. When the Beast's bastard children come of age, they will bring havoc to the lands of the Sword Coast. One of these children must rise above the rest and claim their father's legacy. This inheritor will shape the history of the Sword Coast for centuries to come......"