1. How it begins
It was a disturbingly realistic dream. Twilight was having tea with Celestia in her old library.
“Twilight,” asked the princess, “What in the Emperor’s holy name are you doing?”
“I think it's obvious. I’m avenging you.”
Celestia sipped some tea.
“Why didn’t you think to ask me first, whether I actually want to be avenged?”
“I can’t ask you, princess, you are dead.”
“I’m not. Look, I’m eating a cake. Can dead ponies eat cakes?”
“No-no-no!” Twilight shook her head in denial. “You are certainly dead. This is just a lucid dream. I can even control it. See, I’ll make Pinkie come in.”
Pinkie Pie promptly appeared in the room. Without any skin.
“Oh, for fucking sake!” screamed Twilight, “Begone!!!”
The horror disappeared.
“All right, apparently it’s a lucid nightmare,” muttered Twilight. “Anyway, my point still stands. You are dead.”
“I’m not dead,” repeated Celestia calmly. “I am that Celestia which is a part of you.”
“This is just crazy. Celestia never implanted any part of herself in my mind. And I’m not crazy! My mind is not split! I’m not insane! I was insane, and that bloody Kylara didn’t help at all, but I got better. Nothing but clear mind and cold logic for years now.”
“Got better?” Celestia laughed bitterly, “Dear, you got worse.”
“Worse?”
“Yes. You progressed from a scared pony with a broken mind, into an Acolyte Inquisitor.”
“Just who the hell are you? You are not Celestia, I saw her severed head lying on the ground. She IS dead.”
“It’s very simple. I’m the Celestia which was always part of you. I’m your conscience.”
Twilight looked at not-Celestia in surprise.
“So you don’t want me to avenge you?”
“Of course not! The very idea is ridiculous! Twilight, you knew me for quite a while. Did I ever said or done anything that suggested that in the event of my murder I’d like you to go on a bloody stampede? That I considered it to be the appropriate behavior? Come to think of it, did any pony you knew?”
“It was this or death. Should I have chosen death instead?”
“Frankly? Yes. The first time you stood before Rovini, death was the correct choice. You’d be better off,” said not-Celestia mercilessly, “During the last three years you inflicted more damage on your soul than the Necrons did back home. You don’t realise it, because you became really good at ignoring the pain of your own self-mutilation. Just listen to yourself for once.”
Not-Celesta switched to Twilight’s own voice:
“Cut them down like the animals they are. No pity, no mercy, no regret. Let your sadness and loss fuel the fires of your hatred. Does this sound like you? Does this sound like a pony? I think not.”
She sipped some more tea.
“However, I can’t blame you… well, blame myself, really, for not wanting to die. I can blame you, though, for not getting your shit together. What are you doing??? You know you are immortal, right? And your power grows with experience. And the Imperium can sometimes be surprisingly pragmatical. Be a good obedient bitch for long enough, and Rovini will make you full Inquisitor, mark my words. In time, you could become his superior, even. Spill enough blood for the God-Emperor, and they WILL forget you are a xeno. Is this where you see yourself in a thousand years, when you are older than me, when your last memory of home is extinguished? Sitting in a cruiser, reenacting the same play again and again and again? Twilight Sparkle, HERO OF THE IMPERIUM! Is this what you want?!?”
“No!”
“Then what do you want?”
“To destroy the Necron.”
“Great. Just great. Eliminate a whole race, why don’t you. Don’t stop to consider the possibility that some of them may be innocent. That some of them may even be unwilling slaves to their masters - just like you! Never mind, let's say you destroyed all Necrons. Then what?”
“I’ll kill myself.”
Not-Celestia smacked her forehead with a hoof in exasperation.
“Oh, marvelous. Violent life, ending violently! Are you looking forward to that? Well, you are not going to destroy all Necrons, and even if you kill all those who ruined Equestria, it will not ease your pain, and you know it! In the depth you heart YOU FUCKING KNOW IT!!! It won’t bring me back, it’s pointless. Why not just kill ourselves right now?”
Twilight considered this proposal.
“I don’t want to,” she said quietly.
Not-Celestia glanced at her.
“Ah, self-preservation. Can be both a blessing and a curse. Well…?” she said, suggestively.
“Look, I understand what you are trying to tell me,” said Twilight, “But I already thought it over. Thought about it for months. You know I did. Read a lot of books, too. You can’t make this world better. It is a perfect orgy of death and destruction. No one can fix it, even if by fixing you just mean one side having it all their way. The Emperor couldn’t fix it. Abaddon the fucking despoiler can’t fix it. The Tau are morons for thinking they can. Only the Orks are satisfied - expect that, very ironically, they are never satisfied, there is never enough fighting and enough dakka. I’m sorry, Celestia, it’s hopeless. I’m sorry.”
Not-Celestia’s eyes narrowed.
“You are not trying hard enough.”
“I don’t know what to do.”
“You are the princess of Friendship. Where are your friends?”
“They are dead.”
“Make new ones.”
“I’ve tried,” pleaded Twilight, “I can’t make friends with soldiers, they die too fast. Most of them don’t even want any friends. It hurts them to watch friends die.”
“Make friends among those who won’t die as easy.”
“I can’t! They hate me.”
“You are the princess of Friendship. Make them love you.”
“I hate them myself.”
“Then you are already dead,” said not-Celestia and turned away.
A curtain of darkness fell and Twilight was alone, staring into the emptiness of her mind.
“No,” she said quietly, “Please. Don’t leave me. I’m lost. I don’t know what to do.”
“Twilight Sparkle,” said the voice of not-Celestia, “For the sake of all that is still good in you, please, come back to life.”