.: Awaken, my gem. There is much to do. :. Twilight let out a adorable yawn, rubbing her eyes as she smiled happily at her mentor and king. Shaking the sleep off, she diligently got herself ready for the day and reported to their usual training spot. She stared up at the ceiling where her mentor usually appeared from in the morning.
 
“Good morning, sire. Are you well today?” She asked, bowing her head to his greatness. Black mist slithered down from the ceiling, revealing a more steady image of the former King.
 
.: I am well, my gem. Are you ready to begin today’s lesson? :. Twilight nodded, excited to learn more things from her mentor. The old king knew things that Twilight couldn’t imagine learning about elsewhere. He knew many magic’s lost to time and history.
 
“Of course, sire! I wish to serve you in all things.”
 
.:As expected from my precious gem.:. He moved to circle the filly, watching her closely as he spoke. .:Today will be a bit different. I want you to cast dark magic for me.:. Twilight unconsciously flinched at his orders.
 
“D-dark magic?” She echoed, uncertainty dripping into her tone for the first time since being taught. She’d enjoyed learning about lost magic but dark magic was something only whispered about. It was always told of in the context of curses and tragic endings. It was something to be feared, right? “Isn’t that forbidden?” Sombra’s eyes narrowed at her words.
 
.: Are you questioning my judgement? :. Twilight shivered at his tone and quickly shook her head.
 
“N-never, sire! I’ll get started right away.” She replied, bowing quickly and closing her eyes. She didn’t bother asking her sire how to perform the spell. He’d made it clear that she had lost that right and now had to go on gut instinct. The few stories that spoke of Dark magic in any detail said it was fueled by emotions but was unclear what. She tried to think of something to focus on but her king’s gaze on her back made her nervous. After a few minutes of silence, Sombra grew impatient.
 
.: What are you waiting for? Cast the spell. :. He demanded, making Twilight more nervous than before.
 
“I-I’m trying, my king but…” She tried to cast the spell but nothing happened, nary a spark. “I can’t…”
 
.: …Is this all you can do? :. Twilight’s eyes snapped open at the chill in his voice.
 
“Eh?”
 
.:You are showing yourself to be a disappointment, child.:. He grimaced, as if the sight of her alone filled him with disgust. Twilgith couldn’t say anything as he continued. .:Perhaps it was wrong of me to take you in. It seems I’ve wasted my time attempting to teach failure such as you. :. Twilight’s heart clenched at his words. She turned to him, tears beginning to form in her eyes.
 
“N-no, sire, please.” She pleaded, not daring to take another step closer as she felt his ire. Even in his mist form, his anger filled her with a sense of dread. “Give me more time, I can-”
 
.: Time is not something I have to waste of a waste of flesh who can’t even perform a simple spell. .: He snapped, glaring down at the filly. he let out a disgusted tsk before turning away. .: I had wondered why you ended up running away and now I see the reason. You are not worthy of your horn. You truly are a failure. :. The little filly’s heart stopped, the edges of her vision misting over as she watched her precious king shift away from her. He was leaving her. He would leave and never return.
 
“S-sire? Sire, please, please don’t leave me!” She begged, fear clogging her throat as she struggled to think through her emotions. Everything was fuzzy. Her king was going to leave her. She had failed him. N-no, she couldn’t… She couldn’t lose him. “Sire!” She shouted, her horn burning with magic black as ink and bubbling. From the ground, several deep purple shards erupted from the ground, glimmering beautifully but Twilight failed to see them through her tears. Fear and rage was chocking her, her tears burning a path down her cheeks. It was only the soothing touch of her king that brought it out of her.
 
.: Ah! I knew you could do it if you tried, my gem. :. Sombra sighed, stroking the filly’s back as reality slowly returned to her eyes. Her eyes were wild, looking as if she’d just survived a near death experience. Sombra smiled as he saw the desperate need for approval shine in his protege’s eyes. .: Good work, my precious gem. :.
 

 
The second installment of the Dark Star AU!
 
This one came out… weird but not bad, i think. Just a little different than I expected. Anyway, this takes place a few years after the last DS pic. Twilight has been learning basic magic and spells from Sombra and has grown to admire him. While she still adores Celestia, Sombra holds a special place in her heart. However, her past dealings with failure has made her very dependent on Sombra for validation, which the former king uses to both control her and push her limits. As he feeds her desire for validation, Twilight grows to obsess over Sombra, to the point where his disapproval causes her to lose her shit.
 
And yes, this does relate to how things go so wrong in the Crystal war.
 
Note: This is also the moment where Twilight earns her cutiemark, a black crystal star surrounded by smaller stars.