Is there really any declarative proof that the humans created the cherubs? It seems more like speculation, but a speculation I would support nonetheless.

Go back to the pesterlog Aranea had with Meenah right after she came back to life.  Aranea gives the reasoning for coming back as  “ ARANEA: If I can stop this universe from 8eing cre8ted, then the young Lord of Time will never have hatched in the first place.”

As well as Earth and the Trolls’ Meteor being in the cherub universe, we can assume that the children’s session creates the cherub universe.