The Cipher of Damnation

The Cipher of Damnation is a powerful warlock spell used to corrupt and dominate the power of the Elements. It was kept as a tome that was later scattered into three fragments. The cipher is seen during quests in Shadowmoon Valley and the alternate timeline Tanaan Jungle. The cipher is ancient; the Apexis had writings about it located in Kra'nak.

History
During the Genocide of the draenei, the mad warlock Gul'dan needed to sever the connection the orcs had with the elemental spirits of Draenor to ensure their demonic corruption would be complete. He used the Cipher of Damnation on the mighty fire elemental Cyrukh the Firelord. Using Cyrukh's power, Gul'dan ensured the orcs could no longer hear the spirits and corrupted the land. In the process, a massive volcano called the Hand of Gul'dan was raised at the site of the ritual and the once pristine Shadowmoon Valley become vile with demonic corruption. Many orc shamans, even former shamans like Oronok Torn-heart, perceived a profound sense of loss within themselves as they felt the severance.

After the orcs left Draenor to invade Azeroth, the cipher itself was left behind in Gul'dan's quarters in Karabor. When Illidan Stormrage became the new Lord of Outland, he discovered the cipher in the Black Temple. Not wanting the past to repeat itself and potentially saving it for himself for later use, Illidan separated it into three pieces which he gave to three of his lieutenants: Veneratus the Many, a Coilskar tribe naga, and Ruul the Darkener. With the help of an adventurer and his sons, Oronok Torn-heart recovered the fragments and used it to call for the now-insane and corrupted Cyrukh the Firelord to at last put the elements at peace.

Alternate Draenor
On the alternate Draenor, of that world ordered both  of the Bleeding Hollow and Shadow-Lord Iskar of the Sethekk to search for pieces of the Cipher.

Gul'dan later discovered the hidden location of the Cipher at the Vault of the Earth after one of the Guardians of the Vault was captured and tortured by the Fel Horde. The Lord of the Shadow Council and his agents proceeded by traveling to the Vault and slaughtering almost all of the Guardians, before claiming the Cipher and traveling to the Corrupted Refuge in the shadow of the Throne of Kil'jaeden. Gul'dan intended to use the Cipher to empower the elemental lord Cyrukh, driving it insane before unleashing to ravage Draenor, but he was foiled by the combined efforts of the commander,, Exarch Yrel and the former Shadow Council lieutenant Oronok Torn-heart. The Cipher was then shattered into four pieces; three were collected by the shaman to be scattered across Draenor whilst the fourth piece went unnoticed.