Valanegos was born as a dragon of the Blue dragonflight thousands of years prior to the War of the Ancients. Around the time of the collapse of the Well of Eternity in Zin-Azshari, Valanegos and a group of other blues happened to be in Suramar to primarily learn more about the night elven people there. However, they were caught in Suramar City when the barrier protecting it was raised, and for the next ten thousand years they were trapped in Suramar. Under the guise of a night elf named Valan, Valanegos came to the Grand Magistrix Elisande and offered his services, and he began to work underneath the leadership of First Arcanist Thalyssra with his fellow blues. Without moonlight, and having to feed off of the energies of the Nightwell, the night elves of Suramar changed into Nightborne, and so did Valan and his blues.
Once the barrier protecting Suramar from the Burning Legion was brought down to let them in, after Elisande made a pact with Gul'dan, Valan and his blues were finally able to take their leave, but did not escape yet. Especially after the supposed death of Thalyssra, who had rebelled against Elisande, having made the pact. At some point, the human paladin Drasgar Emsworth arrived in Suramar City under the guise of a Nightborne citizen, which Valan saw right through. He asked him what he was doing in Suramar, and he replied by saying Valan's presence was odd. Realizing that the human had nearly seen through is Nightborne guise, he told Drasgar to meet him at the mountain above the Crimson Thicket. Valan and the blues then made their escape, and returned to their former base of operations in Suramar, inside a massive cavern in the mountain north of Suramar City, where they met up with Drasgar again. Valan could finally return to his true form as a dragon, and he saw that he and his comrades had changed in their dragon form, just as they did their Nightborne form.
Then, he had a sudden lust for arcane energies, like most Nightborne did, and realized that after thousands of years without being a dragon, he and his flight had adapted to the Nightborne ways, and this worried him. He learned from Drasgar that Malygos was dead, and that the Dragon Aspects no longer had their original powers bestowed upon them by the Titans. After taking all this in, Valanegos declared the Blue dragonflight in Suramar be renamed as the Ebon dragonflight, and he would lead them. Drasgar also told Valanegos that there were still Blue dragons on the Broken Isles, in Azsuna. Valanegos said he would return to Senegos in time, but he had to lead his people in Suramar. His new goal was to make sure his people remained intact, as their new magic addiction would surely get in the way of everything they once stood for.