Day of Judgment

Can I rotate the cross?

Yes.

Must the cross be entirely within the realm?

Yes. Evil can cower safely in the corners!

Does this affect multiple regions, such as the void and subsurface as well?

Yes! The card text uses 'affected squares,' which include surface, subsurface, and void.

How do I properly resolve the banish and damage effects?

Banish Evil minions first, resolving effects (if any) as a result of their banishment. Then, damage all units occupying those six squares.