Blood of the Vala'Suun

The Blood of all Fey
The blood of the Vala’suun (particularly the Solti) is said to have "restorative properties" that activate when infused with the blood humans, the only species with which they are biologically compatible (see elven reproduction).
Elven blood is said to “unnaturally” extend mortal life. And it’s even believed (though such matters have been thoroughly stricken from the annuals of official Wyethian history) that at least several former Kings of Wyeth were suffused with Vala’suun blood (illegally obtained, through terrible rituals) to allow their reigns to continue beyond that afforded to mortal men.
This secret was (allegedly) used to cement the idea of "Divine Right" set forth by the Faith Zenithal, casting the Wyeth lineage as something “far greater” than the average human... The Chosen of the Gods.
Though history may have forgotten these atrocities, the Vala’suun remember.

The Origin of the Blood Mages

It is believed, by very few still alive (nearly all Solti), that Xrie Palax served as "Court Mage" to a former king... Eltheiden Wyeth Palax (rumored to have been born Solti, which would - by default - make him present at the time of Mount Celene's descent, went by yet another name (but one of a vast number assumed) back then. He is thought to be the 1st Vala'Suun counsel to the king, a Solti named Selystaru'un the Willowed. 
Errtheiden was perhaps the first king to fall to the immortal temptation of "elvish" blood. Could he have even passed down this obscene rite to his successors? 
For several centuries forward, many "people of the realm" in Wyeth truly believed that the dynastic line of kings were "god-touched" or "beloved of the Faith." Some presumed some intermingling of blood lines with the Vala'Suun might have had something to do with it. It did, of course... just not in the manner they thought.
Nobody really knows exactly when The Sanguine Order came into existence, as they were clearly possessed of a strong foundation, well before they announced themselves to the world at large. However, if Selystaru'un truly was a former identity of the premier God King of Lentokk, could the seeds for the clandestine order of Blood Mages have been laid within the very capitol of Wyeth? 

The Ritual

The process of extracting the life blood of a Vala'Suun is not as simple as one might presume. Those with any knowledge of the ritual understand that it was a long and drawn out experience. Allegedly, the donor needed to be alive during the entire proceedings, even past the point where blood loss of such magnitude would kill anyone. Well, anyone who wasn't being preserved by the ritual's machinations. Alive and conscious. The two primary necessities involved with the "transfer" from elf to man. 
Might it have something to do with the significant presence of the Eret Si'nu within Vala'Suun hemoglobin? Forget not that these "magical molecules" are said to possess an alien intelligence that remains in constant communion with those who know "the ancient ways." Perhaps it is this bond between Eret Si'nu and elf that forces such an inhumane requirement upon the priests performing the transference ceremony.  
It is said, in cases of "superior" donors of "high noble" blood, meaning here, the Solti, that the Lord of Death, Ryktuss himself presided over the ritual, guiding the hand of the Sanguine Priest culling the precious fluids. So much of what we think we know is based on old superstitions and some degree of fear mongering, brought to light in the wake of the Lentokki exodus from Hariel Majour.
However, if but a mere fraction of the stories are true, the implications alone could upset the balance of the entire Western Kingdom.

The Deeper Mysteries

Part of the story that never seems to survive the majority of tellings involves a rumored aspect of the blood ritual... or more to the point, the blood itself.
What separates man from elf is partially the "will" of the blood. Man is a creature of the land, risen from dirt, only to return to it in short order. But the Vala'Suun... they are from lands beyond the veil. Places where life did not emerge through natural processes. They were consciously "willed" into existence. But by whom? It is well known that the fey worship no known gods. That they exist on a plateau that also includes the powerful, yet demonic Vu'un. Is it possible they "willed" themselves into their world of Jei'suul? Possibly.
But who's to say that it wasn't the blood itself, that which flows through their veins, to be held responsible? We've seen that the Eret Si'Nu can manifest in material form, as it does when enacting the will of the mages who harness it. Could this alien intelligence have fostered a desire to exist differently than it previously had? To walk the vastness of its own home world? There was no Eret Si'Nu, no magic, until the coming of Celene. An event that introduced Gothenya to the Vala'Suun at the same time. Could it be that the power we allow ourselves to believe is servant to our whims is instead the actual puppet master? The Boorka have a saying. "That which we cannot understand, stands the higher ground." Just because we only conceive of the Eret Si'Nu on a level not yet approaching mere fundamentals, doesn't mean that it doesn't perceive and conceive us. Who is the master and who is the servant? 
But back to the lost anecdotes of the story...
It's said, by the few who remember, that those humans "blessed" (or is it cursed) with the blood of immortality, are forever changed. Not just in their biology, but in their very essence. Their personalities "shift." They begin to take on different aspects. Things never before present in their demeanors. It's not simple enough to presume that they somehow inherit a portion of the donor's soul. It's far stranger than that...
It has something to do with the ritual. The slow torture. The necessity for a living donor. 
Something else passes between those bonded through the flow of blood from one vessel to the next. Something that perhaps points to why the dread lord Ryktuss sought to bear witness to each of these transferences. If the blood can have a will, who's to say that an event cannot as well? The ritual. Does it take on a life of its own. Through the shaping of the Eret Si'Nu, perhaps? What foul life, never intended for this world or any other, finds its first breath with the completion of this "sacred desecration" of elemental life? 
And what have we unleashed upon the world?