Swallowed Sternum
Swallowed by the Rok that roams the Seed of Destruction's dungeon or one of its Variant Falcon or Dra Hawk minions. Collect the remains of those who were sacrificed and take them to Soldier Orbyu at Keucereus Alliance Base.
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.