After using the six Cube Keys and conquering the Assembled Legion in Castlevania, your crew need to access the 2 ladders at either end - 1 ladder has a secret button inside, this leads to a second ornate key, your crew then go to the 2nd ladder, now use 2 Ornate Keys a Skull key an Iron Key and a Gold Key - your Crew find the Unholy Master Key. What does this do? It unlocks any lock but particularly on the Launch Beach. If you remember, Blue Stones I at one end leads you back up to the Launch Beach and two trapdoors over at one end. The master key unlocks these FINAL entrances to hell itself, PREPARE WELL.