Canterlot
Princess Celestia woke with a start. She shot up out of her bed, panting and sweating, and slowly opened her eyes to allow them to adjust. The room began spinning around her as she became aware of a sharp pain in her horn. She unsteadily looked up and out the window, only to see Luna's moon in the night sky.
"What...?"
It hurt to even think. She could feel something... off. As if a massive reservoir of magical power just disappeared from existence, only to reappear in a new light.
Yet, the feeling could not be any more dark. It was the feeling of magic moving unwillingly. It was trying to escape, crying out as it was being drawn into a new master through unnatural means. It was a feeling that had Tirek written all over it.
She reached up and touched her horn, attempting to focus. She wrapped her head in a sheath of her own magical energy, clearing the drowsy fog from her mind.
The room finally stopped spinning around her, but the feeling did not pass. She dismissed the possibility of this feeling being from a nightmare or the like. If it were that bad, Luna would have felt it in her and intervened. Besides, it was all too real, and it was getting worse...
No, it was getting closer, and fast. She could feel what it was now; it was a magical death scream. Some extremely powerful creature had met its end, and the magic was ripped from its body before it could naturally move on.
"I need to get Luna and Twilight... Tirek could be returning. That shouldn't be possible already..."
The force arrived right there and then, before Celestia could even stand.
She felt it just before it reached Canterlot. It was like her own magic was attempting to flee. Every Unicorn in Canterlot felt it. None were quick enough to react, not that they would know how to. Nopony knew what exactly this was, never mind what it would do or how to stop it.
Every window in the palace shattered at once, as the green shockwave passed through it. The sound came three seconds later. All she could do was shield her face from the glass shards with her hooves and forelegs.
The Hive
The feeling... the power... it was beautiful. Twilight's hooves were not touching the ground. She was being suspended by the pure magic she was absorbing from the dead Queen. It wasn't the same sheer power of the three other princesses, but it was more... satisfying. Her eyes remained dull green and crimson.
The magic of Queen Chrysalis weaved through Twilight, entering through her mouth and building to a crescendo in her horn. At first, it simply built upon her own magic. Now, it was slightly pulling away from her.
She was expecting this, as magic never willingly goes unless the former user gave it freely. When it is forced, it tries to return to its old master. The powers Tirek absorbed were individually too weak to resist, but this was the power of a Changeling Queen, and within it, the power of the Hive.
And it was becoming too much. It was escaping, and the magic she was able to capture began to crawl into her mind. She found herself unable to focus on keeping the magic inward. It seemed like the more she struggled, the harder the magic fought back.
I control you now. Obey me! She was slowly rising upwards, further into the air. She redoubled her effort, adding more Dark magic into the spell. This only caused her more strain, as she tapped into the last of her magic reserves. The nature of the Dark magic forced her to call upon memories of sadness, evil, and strife.
She continued struggling against the magic pushing out. She felt like her head would burst open from the magical pressure expanding in every direction. She fought even harder to keep it in.
Considering the amount of magic moving in Twilight's head, she was lucky her horn didn't literally explode when it finally released. Her eyes rolled back into her head, turning back to their natural color in the process.
The green glow around her ceased, and she fell to the ground, unconscious. The remaining magic began building into a massive sphere, forming around Twilight and the body of Chrysalis.
The Changelings all immediately ducked for cover. The magic kept increasing in strength, until it could no longer hold itself together. A massive shockwave of green exploded from the epicenter, shattering stone and piercing the ground.
It was all darkness. Cold and empty, and strangely comforting.
Twilight slowly opened her eyes, only to shut them at the light that blinded her.
"My... head... Goddess, what happened?"
She once again slowly opened her eyes, allowing them to adjust to the brilliant light. She expected to see the browns and greens of the ceiling of the Hive, but instead saw yellow sky. The ceiling was completely blown off of the Hive throne room. She noticed that the ground was now soft sand, instead of the hard stone it had been before. The entire room had been dark save the fiery braziers leading to the throne, which were now also completely gone. Now, the room was naturally lit with sunlight through and through.
She pushed herself off her back with her hooves, only to see countless Changelings surrounding her. Their stares were mixed, from content, to curious, to uncertain. But, no anger. Anger is all Twilight could have expected from them, but there was none of it. None of the abhorrent hate that was in their eyes during the siege of Canterlot, or the determined looks of anger as they helplessly watched their Queen die.
That's when Twilight finally acknowledged what she had done.
W...w... what have I done? How could I...I... I'm a murderer!
Her mind swirled. She wondered how she could have been so remorseful when killing the first drones, and then so hateful while in combat with the Queen. She wondered how she could bring herself to murder the leader with such impunity, with no second thought. Yes, Chrysalis was responsible for every action of the Hive, but to actually end her life... somehow, it was unthinkable now. That brought about her greatest worry...
How could I kill her with such hatred, but regret it now?! Am I totally losing it?!
She buried her face in her hooves, not caring about all the Changelings watching.
What will my friends think of me when they find out I'm a cold-blooded murderer? What will Celestia... Oh Goddess, I used Dark Magic! I drained the magic out of another living thing! I'm no better than... than Tirek... I don't know what came over me! How could I let this happen?!
Tears began flowing down Twilight's face, leaving streaks in the dusty dirt that was covering it.
I can already picture what they will all do... Applejack will be disappointed in me, I was dishonest... I swore I would never use Dark Magic again. Fluttershy and Pinkie... they won't say anything, and Pinkie's mane will go flat like it always does when she's upset. Rarity won't even look at me... and Rainbow...
Twilight felt a lump form at the back of her throat as she thought of what Rainbow Dash would say, or what she would do.
Celestia...
The lump got even more unbearable as she thought of her former teacher.
I won't be her student at all anymore... she'll take away my wings, and I won't be a Princess anymore, and... no, she'll do so much worse! I'm a murderer, I'll be exiled from Equestria... or... or executed! Everyone will remember me as a filthy criminal and excuse for a Princess of Friendship... I just did something that goes against my own Element! I've permanently tarnished Equestria and Celestia's name! Ponies will blame her for making me a Princess... and... my friends...
Her thoughts were finally cut short with the sound of chitins shifting and hoofsteps approaching. She opened her eyes and wiped away the tears so she could see again.
Aaaaaand I just embarrassed myself in front of an entire Changeling Hive... icing on the cake. I bet Celestia would enjoy that cake....... I am so losing my mind.
She felt a hoof touch her back. She swiftly turned to face the Changeling that touched her, and he pulled it away sharply, taking a step back.
Twilight could deal with the lack of anger, and even the overall look of acceptance from the Changelings, but what happened next was just too much.
The Changeling looked uncertainly at Twilight, before taking one more step back. He closed his eyes, tilted his head down, and bowed.
The other Changelings of the massive group began to look around at their brothers and sisters, until a few more began to follow suite. Then, a few more. Then, a dozen more, and then more, until all of the Changelings of Queen Chrysalis' former Hive were bowing to Princess Twilight Sparkle.
Twilight didn't even know how to think or feel about this.
"My Queen."
Tartarus
Tirek smirked as he gazed through the looking glass portal, seeing the Changelings bow.
"So... she has not learned to use her power to it's full extent yet. That will come with time... but time is what I sorely lack. No matter, she will come for me eventually. All she needs is a little... persuasion."
He closed his hand into a fist and swiped it across the portal, causing it to fizzle out and vanish.
"I will have my pound of flesh yet, little pony Princess..."