[Speculation] The Female Darkin, Blood Magic, Roman/Jewish/WoD mythology
So if you're following the lore developments recently we have
-
Blood magic was given to humanity by the Darkin
-
##Vlad is thousands of years old
-
##There is a female Darkin who is very dear to Varus
While contemplating that some very Old Testament elements of Darkin lore became apparent to me: their resemblance to demons, the possession/corruption/dark magic mechanics, and the very Hebrew naming conventions: the "aa" in Aatrox and Rhaast is very common in Hebrew names (Baal, Aaron, Haagenti), especially among demons.*
##With this in mind I thought of a Jewish/Roman legend that in popular culture pretty much describes the origin myth of vampires. https://i.imgur.com/L7UCfNw.jpg
Do you know the legend of Lilith? Supposedly Adam's first wife, who eventually left him because she was too powerful to obey him, and was henceforth mentioned as a demoness who mentors witchcraft and causes the death of infants. In Roman Christian mythology she has decidedly vampiric qualities. In the Zohar, one of the holy books of Judaism, she meets another familiar biblical character: Cain, son of Adam, who was also banished and cursed after he slew his own brother. Cain and Lilith become lovers for an unspecified period** (from the wiki):
However, before doing so she attaches herself to Cain and bears him numerous spirits and demons.
Somewhere here the myth leaves Jewish folklore and enters into popular culture, largely popularised by the World of Darkness games, and then into various vampire books and movies (by the way I highly recommend Bloodlines, sure it's an old game but it's up there with the Witcher 3 in terms of quality RPG experience). It's pretty much the following: imbued with the power of Lilith's blood, Cain becomes the first vampire, the father of the vampire kind, and over the centuries initiates many more into his cult and tribe (WoD lore wiki excerpt):
Lilith identifies herself as Adam's first wife, the original wife of Cain's father. After staying with her for some time, the two become lovers. He realizes that she has powers and magic that he too would like to possess, so he pleads her for these gifts. The hesitant Lilith then prepares an Awakening ceremony by cutting herself with a knife, bleeding into a bowl, and giving it to him so that he may drink.
At this point it's impossible to judge if Riot had/has this in mind. There are pieces of the puzzle thrown about, albeit too few:
Vampirism: Blood magic, obviously, more a blessing than a curse here.
Lilith - A powerful demoness with vampiric qualities, who is a remnant of an ancient race, who bestowed her bloody gift on humanity: The possible female Darkin character, to be released sometime in the future?
Cain - A runaway murderer, running from his crimes, soon to become a master and pioneer of a new type of dark magic: Our boy here? 
Will the entire Dmitri old lore thing be replaced by an encounter with a darkin? I assume Vlad met her in the time before the Darkin were imprisoned into weapons, else it would make no sense for Varus to remember the event.
Hot damn, I have to say I'm intrigued.
*It was said in the comments that not all of these names are Hebrew and that is correct - Judeo-Christian demons often bear the names of pagan gods and idols. I am still curious about the "aa" and what languages it typically appears in
**Take with caution here because Lilith and Cain's relationship varies in different legends: Reading the Zohar she is far more interested in Adam than in Cain; While reading up on this I saw sources stating Lilith was Cain's true mother or mother in law?
#tl; dr: I have reasons to speculate that the female darkin will be a demoness modelled after Lilith, and she will have given Vlad the gifts of blood magic, which he used to become a demigod and the focus of a cult.
encountered in his comic. Blood magic originates with the Darkin.
(Rhaast icon) fights with his host for however long it takes
•
????