Becoming Darkfallen (and especially, in subset, Vampyr) changes their genetic material, their physical bodies, their way of life, how they view themselves (to the point they soon consider themselves utterly foreign âa different speciesâ to typical elves), and even whether and how they can reproduce. They cannot have children with non-Darkfallen elves and their physical needs and wants are different to the point of near-incompatibility.
Change âelvesâ to any type of lizard and youâd have an obviously different species, let alone the more nebulous concept of race. The latter, in any more fantastic setting, tends often instead towards a group of people with inherited or inheritable cultural traits and/or factors that would, in their context, cause one to form or act per those cultural traits.
In any sci-fi, if a group of a certain people were mutated to the point of being incompatible and unable to have children with other races, and of highly concentrated identity due to their unique and significant needs (e.g., drink blood or wither away)⌠theyâd almost certainly be considered a new race, at least after some time has passed to create obvious cultural identifiers.
If an undead elf was still strolling around elven cities, getting along with everyone, but occasionally needing a blood bag, sure, theyâd just be an elf with a peculiar mutution. When they have nothing in common with other elves beyond their vestigial fleshbags (themselves highly changed), thoughâŚ
Not just humans. Elves, likely even dwarves, gnomes, etc., though that far up into NE Lordaeron itâd be mostly humans and elves who were killed, raised, and then incidentally lost (failed to be subsumed into the Scourge).
Apart from that, thoughâŚ
Whether the Forsaken are a separate race or not is a bit ambiguous, too, only because itâs not a collective identity born of their context so much as a political-cultural reaction to their part (formerly) within the Scourge.
As with the âBlood Elvesâ, not all undead âeven those freed from the Lich Kingâs controlâ joined that group and the Forsaken did not densely nor thoroughly differ from those other, shall we say⌠Free Undead.
- Literally mutating yourself and your children from supping on Fel magic, especially if to the point of having different physical needs and consequent societal ones? Sure, thatâd be a new race. Saying â---- the Allianceâ and deciding to focus on a more autocratic nationalism to protect your own people and eventually rebuild your nation does not make a new race. Similarly, saying âWeâre all [Free Undead] and our former people donât want us back, so letâs make our own pseudo-nationâ is a bit more arguable, but at least not immediately of a different race from any other [Free Undead].