Noctae was one of the Ancient Owls and the co-creator of the Hex Machine, along with Aegolius. There is the Book of Noctae which describes the Owls' history, but it wasn't written by him. The only way to 'talk' with him is in the Eternal Sanctuary. His hologram is to the left of Aegolius's hologram, hidden behind a wall.
Spoilers Ahead!
Noctae's Dialogue[]
... I am Noctae.
Surnia convinced me to leave a message behind.
I don't think even Aegolius knows.
But I'm unsure what to say.
Mathematics and Philosophy are my callings, and the calling of my House.
I never was one for talking, unless someone could pull the words out of me.
Mathematics never lies.
It makes predictions.
If you master mathematics sufficiently, you will find that you can make extraordinary predictions.
The trajectory of a rock. The orbits of the stars.
I learned those as a boy.
Now, as my maths is better, the predictions I make are somewhat different.
I predicted my own death to one of Aegolius's machines.
Not once, but again and again in infinity.
No matter how I adjusted the parameters, I saw my own death there as an eternal wave function, over and over.
And applied correctly, I could see every death. Every life.
Even a young owl named Otus, who dies in a great battle above a floating city.
And yet, Otus, my maths tells me that you will be at this hologram.
A strange inconsistency.
... Perhaps our Hex Machine worked, after all.
Tomorrow is the day that I die, Otus.
It is my hope that by doing so, my prediction will come true.
... So that I will see you here today.
And perhaps in the next Loop, I will not have to die after all.
Maybe then I could spare Aegolius some grief.