Final Order
Defeat the Excuro and Krator of the Cruma Tower, the Grandis of Giran, the Timak Orc Overlord of Oren, and the Lakin of Aden 3 times.
Not dropped by monsters.
Cannot be spoiled.
The chances are official (x1). On servers with x10, x100 and higher rates, drop and spoil come more often.