Zetsuen no Tempest

[Buffalobiian]

Well who says that there is only one mage of Exodus?

I'm assuming by "Mage of Exodus", they're saying something like "Princess/Prince of Exodus" and not just a random mage of the opposite fraction.

The princess was born to protect the Tree of Genesis, and that's their reasoning for the existence of a Mage of Exodus. The clan's just randomly been around. I'm going to guess that they've never met an Exodus clan in all these generations.