I agree that my theory probably has holes but this is what sold me.>the sixth impact and the split are related, but the latter didn't happen because of the former
There is a hole in the history of the world. Sensei talks about cataclysms and says Humanity has split, and clearly the purpose is trick gems (and therefore us, the readers) into assuming the cataclysms caused the split. He didn't say that. We don't know what caused the split. It appears more and more evident that Sensei prefers misdirection to lying, so every words need to be analyzed for trickery, and this is one of the most suspicious sentence in the story. Sensei won't say how humans got splitted but the lunarians say Sensei is a robot that comes equipped with a soul slicer weapon module (?) or something like that. It's altogether too suspicious. I am willing to bet that the same japanese word for "split" is in both pages where Sensei says humanity was separated and Aechmea describes what Sensei can do. >ch 64, he can't talk about what happened to humanity
My guess so far is that the Professor expressively forbid Sensei from talking about it. Everything points out it has to be an order from a human and he's the only human he came in contact with.
I can sorta see the situation go like this:
Professor: I'm not convinced humanity should come back, I mean we kinda destroyed the world six times. What do you think?
Sensei: It is my duty to pray. I am programmed to serve.
Professor: I want you to decide for yourself whether to pray or not.
Sensei: Emotions are a defect. I will pray if asked. Give me the order.
Professor: I will not. You should decide. You are not a slave, your are my companion, you are free.
Sensei: I do as I am asked. If anyone asks me to pray, so I must. If you won't give the order, perhaps another will.
Professor: Then I forbid you to talk to anyone about praying. If nobody knows about it then nobody can give you an order. Go out there, live your life and choose.