BLIGHT SYRUM
Blight Serum - Official Dead by Daylight Wiki

BLIGHT SYRUM ORIGINS

The serum was originally developed by Talbot Grimes to empower humans, but after being brought into the Entity's realm, he discovered Vigo's journal, which described Vigo's own serum made from Pustula flowers. Talbot, now known as The Blight, became mutated and feral after a high-dose self-injection, and both continue to use versions of the serum in their respective pursuits.

HOLLOW BLIGHT SKINS

Hollow Blight Skins are (As the name implies) skins for killers where they are infected by the Blight Syrum. The one responsible for injecting, and mutating the killers is none other than Talbot Grimes (aka Blight).

my wish for one of the blight skins — BHVR

If you weren't aware, all blight skins show the syrum injected into the killer (Usually into their back). And on each Syrum is a tag, these tags are all different. each tag has an alchemy symbol and numbers to go with it. Some of these symbols and numbers include...

Spirit - Air 2825

Hag - Putrefaction 1227

Clown - Spirits of wine 1130

Plague - Borax (also known as sodium borate, sodium tetraborate or disodium tetraborate) 2514

Nurse - Acetic Acid 2330

The original killers (Being Trapper, Wraith, Hillbilly, Huntress, and Doctor) all have the same tag. Each having the numbers 2114-25, and strangely has the alchemy symbol for copper.