He, like many others, ended up feral. He was also trapped in the Emerald Dream, along with the rest of the worgen. And as such, he also ultimately ended up in Shadowfang Keep, under Arugal.
After Arugal's death, Valar(still feral) wandered away from the Keep, eventually reaching the Eastern Plaguelands. He was risen as a Death Knight to serve the Scourge, and trained as an initiate in Naxxramas. He was killed during the first invasion of Naxxramas by the Argent Dawn, but was risen along with everyone else when the Dread Citadel was moved to Northrend.
In Northrend, he continued his training. Because of his promising potential, he was picked along with six other Death Knights with the same promising potential, to be a part of an experiment.
They were forced to rip their own hearts out, and have their souls shattered. Out of the seven Death Knights chosen, he was the only one to survive, the others having gone insane and killed themselves.
He was relocated to Icecrown after his training was complete, guarding the Cathedral of Darkness. He stood watch there as Tirion Fordring and other heroes destroyed Arthas' heart within. With the destruction of Arthas' heart and his sudden weakening, he was free from the grasp of the Lich King and the Scourge.
He wandered Icecrown, eventually reaching the Shadow Vault, where he was taken in by the Knights of the Ebon Blade. His quick transition from Feral Worgen to Worgen Death Knight had left him with no memory of who he was, and thus was unable to tell the Knights his name when they asked for it. They soon gave him the name "Wolvigar."
Wolvigar had new purpose after joining with the Knights. He fought against the Scourge, and had assisted in storming Icecrown Citadel, fighting in the halls when the Lich King finally fell.
After the war in Northrend was over, Wolvigar was relocated to Acherus, where he quickly rose through the ranks until he reached the rank of Knight-Lord. He served as a teacher, a soldier, and an ambassador for the Ebon Blade until his eventual departure from it.
These days, he simply travels around the world, helping those in need and protecting those in danger.
And he's occasionally fondled by women who're into that sort of thing.