Yes, it is a testing island. But this is a good time to join, and the codebase between testing and stable islands was recently synced, so all islands are, for the moment, mostly the same. And if something does break... meh... roll with it.
As for religion... Zakilevo is referring to
Sanguis Astroism. It is by far the largest religion ever in BattleMaster. We have over one million common followers, and something like 140 nobles, as well as over 100 temples. There are currently five theocracies with SA as their official religion, a few more realms where it is the major or only religion, and the rulers of two more realms who follow it as well.
