"I welcome you to the Vault."
I looked around the new room before getting significantly freaked out. The room was very intimidating, and while Celestia did call me a prince, she could have simply been doing that to lure me down there. I began to back away hoping to sneak out before she noticed. She did.
"Please, Prince Taylor, stay. I know you do not have much reason to trust me, but please understand that I brought you here for a reason." she said to me while facing me. I could see in her eyes a sense of softness as if she was trying to connect.
"I don't have a reason to trust you. You haven't told me anything, you had your student kidnap me, and now you brought me to the center of the mountain where it is being guarded by automatons with magic. I'm sorry, but when the god of chaos is more trustworthy than you there is something wrong."
She sighed deeply and closed her eyes. Several moments passed before she opened them again and responded to me. "I'm sorry that I haven't given you many reasons to trust me, but you needed context for the reasons behind my actions. That is why I brought you here."
"You brought me a mile into a mountain, for context?!"
"Yes."
"Why?"
"Same reason that Doctor Stable told you about his theories about your condition before treating you at all. It is so you can better come to grips with what this is all about."
I thought about that. It made sense, I didn't understand where my power came from and I was scared of it. I got explained about how it worked and I was willing to learn to control it. I didn't know if I was sane here and was told that I was in an alternate universe and I learned to accept this new world. Maybe her giving me context now will bring acceptance to something else. "Alright, I am ready to have you tell me what you needed."
"Thank you. How many people did Discord tell you of them being agents of Decay?"
"Him, me, Death, and Sombra. And I got told of Nightmare Moon and Chrysalis by Spike."
Something about that seemed to have struck a nerve with Celestia, though she quickly recomposed herself. "Those have been the largest players of Decays work for certain, though there have been others. A couple of them had been The Smooze and a Lord of Time."
"Wait, the Doctor is an agent of Decay? But he was the protagonist!"
"Indeed he was brought here to be an agent of Decay, but he had been lying low since he got here and quieter still after we acquired his mode of transportation."
"You stole his TaRDiS?"
"We collected it and he made no major moves to reclaim it. We took that as it was not a major point of contention for him."
"Unless he didn't know you had it. So I hope you don't mind but I will be telling him such when I see him next."
"I won't dispute that. Not yet at least." Shudder. "Besides the Smooze, there are two things that they all have in common. Do you know what they are?"
I paused for a moment. "Well one is that they are all powerful, I would guess."
"Correct."
"But I am not sure what the other is."
"They are all masters of others from one time or another."
"Excuse me, could you paraphrase."
"They were all kings."
"Wait, no that can't be."
"Why not?"
"The Doctor is no king."
"But he had married a queen in his time and why would he call himself a Time LORD."
"Well what about the Smooze as you called him. If he didn't fall under this branch there has to be more exceptions!"
"The Smooze was a mindless form that absorbed magic and grew from it. In fact it is a sterilized form of it that protects these chambers."
"Are you saying that that purple liquid dripping from the walls is an agent of Decay?"
"A form of it to prevent it from growing and spreading."
"What of Discord? I don't think that he would ever be king material."
"He controlled Equestria before my sister and I were able to reoverthrow him."
"Death?"
"Lord of the Dead."
"Nightmare Moon?!"
She stopped and looked away from me. Something about Nightmare Moon was most definitely a point of contention when it comes to Celestia. However it was not a look of anger or hate, but one of shame. "Celestia?" I asked her. I did not want her to completely shut down on me here, not when she was in the middle of explaining things. I still needed to know what is going on here.
She sighed and responded to me. "Nightmare moon... was my sister. After the fall of Discord, my sister and I were placed into power. We had to have one of us awake at any point in time out of fear that we would be under attack again. To achieve this we each took half of the day under our control, I the day and her the night. As time passed with me being the pony in charge of the time all others were awake, they began to favor me over my sister."
She walked over to one of the pedestals. Inside it was a dark indigo metal with wisps of smoke coming off of it. "This created a divide between us and she became resentful. She became more and more secluded then she already was. One day she refused to lower the moon and I worried for her. I felt like some time would allow her to calm down so I let her be. A day had passed and she still refused to lower the moon, so I confronted her. I begged her to lower the moon and she refused saying 'There shall only be one princess in Equestria.' It was immediately then that she had given herself to a dark force and changed her into Nightmare Moon.
"I thought that she had become mad, and tried to reason with her, but she became violent and attacked me. While in the past I could have overpowered her easily, I was not a match for her that day. I had to resort to the elements of harmony, something that we had only used in the past together. I was so ashamed that I had to use them that I abandoned that castle and moved here. From the sight where great good resided with the Tree of Harmony, to here, the Vault."
"But that still doesn't explain why you called me prince or brought me down here."
"While I had moved the castle here, I refused to enter the Vault out of my shame. I had hoped that, like I had done in the past, of there was more rulers, we could be better interconnected. Able to take the slack of others when family or friends called."
"But you are still arch-princess."
"I had tried even ruling, and things more often then not ended in a stalemate of ideals. While I control the day to day goings of Equestria, the other rulers could easily supersede me."
"And the vault?"
"If what Discord had told me is correct, you will gain a much better understanding of magic than anyone, Princess Twilight included. There is great power resides here, and I hope that you can help us all understand it."