I've finished all four books and still do not understand the purpose of the Tree of Thorns from the perspective of any of the factions?

2 Answers 2


It's been a while since I read them, so I can't remember in which book this was explained:

The human UI (Empathy) had originally fled from its confrontation with the Machine UI by travelling back in time. The Tree of Thorns was designed by the Machine UI to serve as a beacon of agony which Empathy could not ignore, and would force it to come forward so the Machine UI could defeat it.

  • And yet it was directly connected with the Shrike whose purpose was not so singular - it defended Aenea from TechnoCore which seems against Machine UI wishes (unless AIs were not working towards creating it at the time, I'm not sure what happened with those plans).
    – Deltharis
    Dec 16, 2014 at 22:59
  • 1
    Now that you remind me, wasn't the Shrike implied to be part of the original Death program, designed to reap unfit programs so that the AIs would continue to evolve? In that context, it could've been trying to force the Machine UI and Empathy into conflict to prevent stagnation (if the Machine UI is alone, what's left?). It was also stated at one point (I don't have a reference so I won't add it to my answer just yet), that the TechnoCore has countless factions, some of which feared their own UI's creation. This is all based on my shoddy recollections, so I'll have to look up refs.
    – Liesmith
    Dec 16, 2014 at 23:10
  • It all would have been simpler if Aenea in later books didn't change the canon (I distinctly remember her retconning parts of the Cantos as written by Silenus, quite possibly connected with our understanding of TechnoCore). Have fun with finding those refs ;) In Hegemony era at least, original cantos description, there were 3 factions mentioned, all for UI creation but differing on the method how to approach it so that's not it.
    – Deltharis
    Dec 16, 2014 at 23:21
  • I remember the original three factions, but I also remember that it was later stated that that was a lie, and there were as many factions as AIs. The refs will be fun to find, because I only have the audio version of each novel...so I have 600 hours of research ahead of me. Good thing I love these novels.
    – Liesmith
    Dec 16, 2014 at 23:52
  • Ok this makes sense up to a point in the books, but the changing objectives of the Shrike later on sure do seem to contradict this idea. Confusing.
    – Drew
    Dec 17, 2014 at 16:49

It is mentioned near the end of The Rise of Endymion that Aenea had managed to "control" or "harness" the Shrike, something like that. So its role in the latter two books doesn't necessarily jive with its larger mission.

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