He is Lord Harkon the corrupted Prince of the Falmer.
In the waning days of the Falmeri empire, when the five hundred and more pressed their attack, scattering the snow like incandescent flurries of white. They, the folk of snow sought many avenues of deliverance through great desperation, Lighting the Eye, Knocking on the sky, and Giving into the Pale.
And all met with failure
But Prince Harkon oh hallowed ears he, gave his breath to dark influence. his contempt of man knew no bounds and with his cabal convened with Lord Molag Bal prince of Domination. "Your skin, your visage, so supple so white*. great bravery for one of you to summon me" uttered the shimmering prince.
And they bowed unwavering
"Oh Molag Bal prince of Domination, we call upon your strength. our people dwindle day by day, our enemy grows by the hour." and the Prince smiled as Daedric princes often don't, for he knew the price he would desire before the thought of summoning him entered the Falmeri's throughts
And he smiled some more.
"Your skin, your visage, so supple, so white. submit to me and I will weave renewed strength through all of your kind" and indeed they the Falmeri in their blind desperation were most eager to be blessed by Molag Bal, but little did they know the price they would pay, the horror they would wrought.
And oh did Harkon know
"Yes my Lord, all I bring before you, my personal tribute. the finest of a dying race, make of them to your desire. in return I desire power of the highest order!" and with his words lace a tinge of concern among the disciples, but they remained in reverence.
And woe the fate the await them
With a gesture of his fingers he did summon legion of daedra, vile and ravenous. And they beset upon the gathering of Falmeri, so supple, so white, the pure were corrupted with great prejudice. Prince Harkon stared upon the writhing mass of agony and strife. A tear graced his cheek, but resolve burned in his eyes. He then felt a hand on his shoulder, Molag bal looked down upon him and smiled.
And he was not gentle.
One and a thousand more of all tones, where graced that day and that night and day once more. Mind, body, and soul were touched and what once was so supple, so white, became wrinkled and pale. and did he and his legion disappeared, as often Molag bal does when he has his fill. this scattering portion of Falmeri, corrupted and profane they were marred by the cloak off Magnus and knew little more than to swell their numbers.
And Prince Harkon remained shimmering white.
A Prince no longer, his eyes black as night with ascent of crimson. He a small few possessed what he desired, indirectly bringing another nail into the coffin of his people as a result, they were no longer Falmer. he named those who remained the Volkihar, and the corrupted souls the betrayed.
And of great irony, no retribution
His following was quite small and the Falmeri continued to fall, remnants reside in the eastern isles. but few would join his court, and the cloak of magnus, his final obstacle was most mighty; and so the Volkihar submerged themselves. soon the great Falmer monasteries were forgotten, buried under leagues of snow. The Nords themselves continued to grow, and the Falmeri people were of myth and legend.
*High Caste Falmeri often included snow white tones, of which Harkon was apart of, they also varied among deep blue tones as well.