So, for anyone who played Cataclysm and did the questing for both Horde and Alliance, you learn that Sylvanas’ Val’kyr have limitation on their resurrection powers.
They can only resurrect the descendants of Vrykul into sentient beings. *Learned during Horde questing in Silverpine and Alliance questing… somewhere I don’t recall.
And confirmation that this quest does indeed confirm that they can only resurrect humans:
*Note - he does say she might grow stronger later - but no evidence is ever stated in game that she has.
After she learns of this, Sylvanas targets the human settlements in the Eastern Kingdoms, because obviously, the humans become the only possible target to resurrect, being the only descendants of Vrykul.
During Siege of Orgrimmar, Sylvanas remarks to Lor’themar that she can resurrect his troops (despite no evidence showing her Val’kyr have gained this ability) so they can continue to fight, so chances are she meant as skeletons like at the Battle for Lordaeron.
(It’s also at this time that Lor’themar states that she is never to resurrect one of his people.)
So, what happened? Suddenly, Battle for Azeroth launches and Sylvanas’ Val’kyr magically have the ability to resurrect not only Night Elves as Dark Rangers, but also a Blood Elf? (Lorash Sunbeam, in the books. I’m still waiting for Lor’themar to find out)
Most people seem to theorize that the deal with Helya she made included the gift to her Val’kyr to resurrect other races, as Helya was once queen of the Val’kyr, but with no explanation, the random super charge of her Val’kyr makes zero sense.
So what’s going on here? Why are Sylvanas’ Val’kyr randomly capable of resurrecting more than just humans suddenly?