Cortana: The Lost Story

Company

I seem to have some company today. The radar picked up someone aboard the ship. Like right now. They aren't human that's for sure. It's unlike any signature I've ever seen before. I have to go check it out because it's the weirdest thing I've ever seen. It wasn't like there was a ship that dropped off, no I would've seen that. It just showed up. Out of nowhere. I don't know how and I don't know why but it's here. I think I should try to figure out what it is. There is no reason for whatever it is to pop up in a random destroyed ship unless it sees something. So I just have to assume it sees me. But I don't think it wants to say hi just yet, I know I sure as hell don't want to. So I'm going to go on a little recon mission to find out exactly what I'm dealing with. He seems to be around the control centre of the ship and I am carefully making my way down there now. Ok now I have a good look on the thing and I notice it seems to be a blue and silver creature of some sort. It looks almost like its of Forerunner creation, like a robot. Which would make sense it's said they had made robots to fight for them.
"I see you have spotted me Cortana, I guess I should give a proper greeting. I am a Promethean Knight serving under the Librarian."
"You know who I am?" I ask confused as to what's happening.
"I am a messenger of the Librarian, we have been watching since the beginning, you and your Spartan and destined to do great things." The Promethean answers my question.
"Why have you come to visit so suddenly?" I ask still wanting some more info from him.
"There is a great evil on Requiem, one of power larger than you could ever imagine. Once you get here I need you to find the Librarian, before this evil finds you."
"Anything I should be aware of?" I ask flooded with so much info at once.
"Yes, one last thing... You can never tell your Spartan of the talk we had, or of this Librarian. You must keep this a secret."
"Why" I say wondering why I should hide anything from John.
"He will not understand, he is a great warrior but is not one known to trust many, if you tell him of this he will not listen. He has to find out for himself, only then can he truly understand." The Promethean says explaining the insane request.
"I understand what you mean and I will honour the Librarians request. But where can I find her?"
"We cannot answer that, not at this moment, it is way too dangerous to give away our position now. But trust me, when you find us, you'll know. Anyway I have to go."
Well that was fun while it lasted. I wonder what this great evil is and what this Librarian wants or needs from us. Anyway I have no way to answer that so I guess I just have to wait until we land at Requiem.