The Dark Secret Saga

The Dark Secret Saga is a fantasy story written by the Italian band Rhapsody of Fire, written by Luca Turilli, told under their concept albums. The story is a sequel to The Emerald Sword Saga. Taking place a few years later, it includes one of the characters from the previous saga, Dargor. The story was told largely through character quotes in the CD booklet, in addition to actual voice-overs on the CD tracks, placed intermittently throughout each album.

All parts of the story have been released, split in five CDs:

Symphony of Enchanted Lands II: The Dark Secret is the beginning of the saga. We are presented with the story of "The Seven Black Books" written by Nekron, son of the Hell God Kron. The books, written with angel blood and then becoming indestructible, tell a part of a prophecy known as the Dark Secret. The prophecy would one day awaken the seven demons who would open the gates to hell, releasing every kind of ancient monsters, alive and dead. Nekron would then be reborn to reign again in the unholy name of cosmic chaos, "And this time, he would reign supreme."

A search for the books was conducted. Through the ages, six of the books were found; however, the seventh book, containing the secrets on how to resurrect Nekron, remained unfound. Nevertheless, there was still hope. After he discovered the black books, an angel named Erian had a vision where the Gods of Cosmic Light told him how to stop the prophecy. Erian then wrote, in his own blood, the White Book which revealed how to stop the prophecy. The book represented a threat to the hellish prophecy and to Nekron's resurrection and then, in the age of the Red Moon, 3000 years before, the Lords of the Darklands won their battle against the Army of the Nordic Plains and found Erian's Mystical Book in Ainor's sacred halls. The book was then hidden in the Darklands, in a place known only by the master wizards of the Black Order.

There was hope, however, that the seventh black book held a clue as to where Erian's White Book was hidden, and so The White Dragon's Order, an order dedicated to protect the Enchanted Lands from the Darklands, was founded. A man named Iras Algor wanted to lead a search for the seventh black book. However, no one knew of a way into the darklands. Iras Algor then recalled that Aresius had told him to search for Dargor. Surely he knew the way. There were many objections to this, but Dargor was their only hope, and so Iras Algor, the hero Khaas, princess Lothen and the elven king Tarish, led by Dargor, set out to find the seventh black book hidden in the caves of Dar-Kunor. They took the pass of Erloria, the safer way to reach the grey mountains. At the beginning the journey was full of wonderful visions, in the Dragonlands they found a lot of lovely creatures. But after ten days this sight was over and, when they finally reach the falls of Erloria, the sunlight was over.

...
Wikipedia