Tremelo has gathered a great deal of information about the Island, Black 13 and the tomb it resides in, and also House Cannith and their efforts in unlocking the secrets of all of the above.
The Isle of Dread was once a natural island on Eberron, a mere speck in the Sea of Rage. 3,000 years ago, the elven dragonmarked clan known as House Vol, bearers of what was then known as the Mark of Life, established a secret enclave on the island, where they engaged in clandestine efforts to further empower their dragonmark, which had influence over the stuff of life. Useless for healing, the Mark of Life could infuse life into lifeless things. There is speculation in the notes of Edgar Tolstoff and of the Cannith researchers that the Undying Court may have had its genesis from this Mark.
The mark could also be used to take life from a living being. This application was more or less ignored until the dragon wars began.
When these wars started, The isle of Dread was the elven outpost nearest to the dragon homeland of Argonessan, difficult to supply and susceptible to sustained dragon attcak. To avoid destruction of their secret enclave House Vol entered into a contract with a formian feywild king to hide their island in the Feywild when dragons threatened.
The notes indicate that House Vol also used a connection to the Feywild, a location called The Garden of Graves, to travel between the Isle of Dread and Vor Rukoth, a ruined city apparently dating back to the Age of Demons. It was in Vor Rukoth that House d’Vol first discovered the dragonshard that would be come to be known as Black 13.
House Vol entered into a pact with a small cadre of dragons looking to bring peace to the two races. A green dragon was wed to the heir of House Vol, and the resulting offspring- a girl named Erandis d’Vol- was raised in secret on the Island for the first few hundred years of her life. However infusing a dragonmark with the blood of dragons produces an immensely powerful mark. It was suspected that once Erandis Vol matured and could control her power, she would be able to kill any being she could concentrate on, over any distance. Once her existence was known to elves and dragons, they bonded together for the complete extermination of the House d’ Vol, starting with Erandis and her mother Minara.
Erandis was slain, but Minara, bearer of a sibbery’s Mark of Life (called mark of Death from this age forward), proved unkillable. Her body was all but destroyed yet it was still infused with life- and rage at the slaughter of her entire line.
So a tomb was constructed to hold her remains. Designed by a Eladrin named Alablaq – House d’Vol’s own feindishly brilliant engineer and the architect of the Garden of Graves – Minara’s tomb is a sentient being, like a warforged, and can alter its defenses to counter raider’s efforts.