hi guys I'm the real Eternal Sugar (trust) and this my prediction/headcanon for Shadow Milk's backstory before we get it okay ? okay
The "Fount of Knowledge," Blueberry Milk Cookie, was a cookie baked by The Witches, just like the other Virtues, to be a hero!
In his youth, he spent nearly all of his time learning magic and much more directly from The Witches themselves. He loved the other Virtues, his friends, dearly, despite not having as much time with them as he would have liked.
When old enough and smart enough, he worked at the Blueberry Yogurt Academy of Magic, as the First Headmaster and the first Cookie ever to teach magic!
He thought that his duties were fine at best, not very fun, and he got lots of attention, but not in the way that he craved.
The Fount of Knowledge wanted to be like the dear Bringer of Happiness, who often would visit the Academy to lift the spirits of many students. He favoured her in particular.
Blueberry Milk Cookie dreamed of being an entertainer— a playwright, a poet, a director, an actor, a clown.
That's how he would like to bring joy to others, and himself!
But instead, he was baked to do duties that bore him and brought him no real joy.
He'd made a few attempts— he tried to have school plays, he wrote stories and poetry in his (painfully small amount of) free time...
The Witches did not approve of such activities.
With his work piling up and the overwhelming dread that he'd have to do this same tiring job forever, the Fount of Knowledge was not well, to say the least.
His jealously only grew and grew. Sweet Sugar Cookie got to make people happy. That was her destiny. The Witches baked her for that. Why could he not do that? What about him would not be good for such duties? It made him angry. It made him sad. It frustrated him. It made him so very painfully, unbearably upset in every way.
He'd act strange and erratic, worrying his students and colleagues, randomly dropping painful information on people, lying about things for fun, playing nasty "pranks" on others, trying to convince himself that there must be some other way.
Blueberry Milk Cookie only got worse and worse.
He'd pleaded with The Witches for him to be free of his duties, for him to have something else in life, for him not to suffer this fate so carelessly forced upon him.
The Witches would not pay any mind to such a request.
Instead, they stopped answering his and the other Virtues' calls entirely.
Blueberry Milk Cookie could not understand why The Witches had forsaken him like this.
Sure, it was about the other Virtues, who were having issues as well, but not in his mind.
Whatever did he do wrong?
He knew some things that he did wrong, but what did he do to be bound to this duty at birth?
Just as The Witches had abandoned him, he would abandon what They had made him for.
One of his students was causing terrible damage to the Academy anyway, messing with forbidden magic, turning other teachers into spirits...
He decided to cover up his identity as the First Headmaster of the Blueberry Yogurt Academy of Magic, for what reason exactly is not certain.
From that moment on, he'd do what he wanted, and not be bound to the duties of the Virtue of Knowledge.
That is, until someone would put an end to that madness.
To be chained, restless, bored, and unable to bring anyone happiness once again...