This cipher was used by Gul'dan to sever the bond between the orcs and the elemental spirits of Draenor. When he murmured the words in it, he also created The Hand of Gul'dan and beckoned Cyrukh the Firelord. Cyrukh was also responsible for desecrating the world thus creating the Outlands.
It is constructed by it's three fragments:
The Cipher of Damnation is indeed a powerful incantation. Ancient and chaotic, the cipher itself has been responsible for many tragedies in the history of our worlds. That is to say, it is not unique to Draenor.
The burning symbol you saw was the mark of Kael'Thas. His knowledge of the ancient words explains much.
Your discovery has roused the naaru. A'dal has requested your presence in Shattrath City. Should you choose to come, seek me out at the Terrace of Light.