(Last) The Shadow King's Core (Raid Boss) is a secret boss encountered randomly during questing in the Starless and Bible Black raid event. Secret bosses are only encountered after defeating the two end bosses and the two hidden bosses (at least once each) as well as the 18,000,000 hp secret boss (at least once). They are hit for double damage and the player has 2 hours to defeat them. This boss always begins with 21,000,000 hp.
The discoverer of this secret boss is awarded 12 Hematite Keys if the boss is defeated. Additionally, the discoverer and anybody else who participates in the battle and does at least 1,000,000 damage to the boss is rewarded with 2 Hematite Keys.
This is the strongest boss of the event. The rewards given to all players who participated in the defeat of this boss have the highest chance of being worth more than Power Potions used for the battle.