https://wow.gamepedia.com/A_New_Plague_(3) reveals the Blight is an ancient disease…
Where did this disease come from? Seems it came from Lordamere Lake(https://wow.gamepedia.com/A_Recipe_For_Death_(2)) which was corrupted by Kathra’Natir(https://wow.gamepedia.com/Kathra%27natir#Legends:_The_First_Guardian) who was wielding Apocalypse at the time… Funny how Death Knight Players have the source of the Forsaken Blight as one of their own personal Artifact Weapons!
The Forsaken Blight’s nature is obviously that of every disease implanted into Apocalypse combined! The Dreadlords did their work well!
If Kathra’Natir is infecting Lordamere lake with a Plague capable of killing instantly then why wouldn’t he use every Plague inside Apocalypse as a single Ultimate Plague to get the job done!?! Surely the Dreadlords would be smart enough to make sure their Plagues wouldn’t cancel each other out right?
You wouldn’t need a world-class chimeric super-plague to kill all the fish in a lake. They’re just fish. They’re pretty easy to kill. A dreadlord could probably accomplish this feat just by peeing into it.
And there are half a dozen quests about various Apothecaries studying various plagues, diseases and venoms. It’s kinda their whole thing.
It seems like there have been multiple iterations of the Blight as the Royal Apothecary Society worked towards the mandate Sylvanas gave them at their inception: Producing a version of the Plague of Undeath which would kill the living and then bring them back as a free willed Forsaken instead of a member of the Scourge.
The various attempts to do this likely have been based on various concepts, this one mentioned in this quest is based on an actual disease, others are based on toxic alchemical brews.
Generally, the Forsaken seem immune to most versions, yet there was one strain produced by Grand Apothecary Putress and cohorts which would instead work on the living and undead equally and just… killed.
The fact that the dread lords forged frostmourne the helm of domination and apocalypse and essentially created modern day necromancy is horrifying all in it’s own. The fact that slyvanas had over a decade to pick the brain of one of their leaders is even more unsettling and would account for how the forsaken managed to create the blight and slyvanas learned how to change from banshee to dark ranger and raise the dead without ever being trained as a necromancer. The implications make the future of BFA and wow bleak to say the least
She had one of their leaders running the Royal Apothecary Society. Varimathras obviously had the Dreadlords’ diseases improved upon to make his masterpiece which Putress and Sylvanas both used.
It would be interesting if a Questline had Mal’Ganis or Kathra’Natir trick the Player into charging Apocalypse with Blight which would then end up in the Dreadlord’s possession as said Dreadlord aligns himself with Sylvanas(due to Sargeras being imprisoned).
Hopefully the Dreadlord doesn’t learn of the perfected plague made by Peppy Wrongnozzle(which apparently includes Rotgut) that can harm Vrykul where Varimathras’s Blight can’t!
Keep in mind that the Forsaken Blight has its origins in a bunch of other stuff since its development began. Strains of Scourge plague (including newly developed strains stolen directly from Naxxramas), various fel-corrupted blood samples collected by RAS agents in Outland, myriad toxins and poisons and even reagents gathered from the Emerald Dragonshrine by the Horde player in Northerend. They also incorporated fluids and materials from new species they encountered to broaden Blight’s virulence, as witnessed when it initially proved less than effective against the vrykul in Halgrind and the player was sent to collect the chieftain’s blood so the RAS could boost its lethality against vrykul.
The Blight’s always growing and changing; it honestly wouldn’t surprise me if the RAS makes a point of capturing individuals from any new races they encounter (I’d imagine in secret when said race is friendly to the Horde) so they can incubate and boost new strains of Blight, further expanding its scope of susceptible victims.
There’s no singular origin to the Forsaken Blight. It’s literally a cocktail of lethal things that they’ve thrown together. Hell, the Forsaken Blight doesn’t even act like a disease. It’s more of a melty, spicy limeade.
Off the top of my head, they’ve worked with Darkhound blood, Murloc fins, spider venom, Doomweed, giant crab poison glands, and probably a lot more.
You ever wonder if the dread lords are infact more dangerous without the legion because now they won’t be setting up for an invasion, just creating as much war strife and chaos as possible to feed their insatiable hunger for general desturction?