Going to say it's probably not meant to be Sephiroth, but Sephirot, as in the Kabbalah Sephirot. Seeing as two of the continents were named Hod and Chesed. As well as the whole tree of life thing.
I had a hard time getting into this manga. I liked it, but not enough to keep me hooked. I'm wondering if other people had that same problem, hence the rearing of axe-kun's ugly little head.
Much appreciated for making this. Though I will agree with some previous comments that there were a whole lot like a lot of time skips. But most likely because it nearing the end. A good read to read on the side but not something I would have as a mainline to read.