/\ He meant the zone which was neither good or bad (just neutral).
They're in that order to prevent the demons of the False Abyss from reaching the Hadean Zone and releasing its horrors.
That would be a good idea. Dimidean was inspired from latin Dimidium, which meant half. In my original ideas, the Arborean Zone was supposed to be good and the Dimidean Zone was to be half as good. I say we call it... the Agathean Zone ?