The Maddening Roar
These items, created eons ago by the black dragon Millisandrox, are a set of small, 3-inch-cubed metal puzzle boxes. According to history, Millisandrox, following her interpretation of the Draconic Prophecy, crafted the Rubicons and gave them to the goblin peoples of the ancient Dhakaani empire. The Rubicons were then used to open a portal between Eberron and the distant plane of Xoriat, the Far Realm.
The alien daelkyr and their aberrant minions spilled through the open portals and a great war erupted. In an effort to undo the damage she may have caused, Millisandrox taught the goblins and orcs the secrets of magic to aid them in repelling the daelkyr invasion. After a great, long war, the Dhakaani people were able to seal the portals, defeat the aberrant marauders, and seal the daelkyr deep beneath Khyber with the magic imbued within the Rubicons.
Through hours of research, the party also discovered that the seven Rubicons were originally buried with the heroes of the Dhakaani/Daelkyr war, in crypts scattered throughout the lands that were once Dhakaan, but now range across most of the breadth of the continent of Khorvaire. The party knows the location of these tombs, but they do not know whether the Rubicons remain there.
The Rubicons were named:
Box of Sorrows
Coil of Deceit
Keystone of Desire
Trap of Promise