Oku said:
How do God Learners bind all those elementals and spirits if Enchanting Ritual is a rare spell? Do they call upon zistorites whenever they need some undines for their ships etc? Or when they need some warding enchantments for important places?
No, they manipulate the summoning spell's duration to keep the summoned entity contracted for an extended period. Binding through the Enchantment ritual is somewhat risky as the binding can fail and the entity may react badly to the attempt - or simply disappear. It also means you have to bind Magic Points that you then can't reuse until you drop the binding. Its better to summon something and then continue to extend the spell through recasting.
Also, although the Zistorites have the monopoly on enchantments they are not the only ones who can do it. If you recall, earlier in this thread I mentioned that the Abiding Book has spells in three levels: Common, Order and Forbidden. Enchantment is an Order ritual meaning that only certain orders have access to it. The Zistorites are one such order, but there will be others (although they're not common and quite specialised. They may need to petition the Abiding Book for the use of the ritual).