Oh, some unasked answers.
The disciple works like a prophet and none of the nations can create prophets. So, if you want to have an immovable pretender or disciple, plan to find an alternative way to get Holy 3 units.
Ermor, Agartha, Altantis and Ctis have H3 units. A few have H3 National summons, like Rus. And of course Water 3 gets you the Bishop Fish, which is aquatic.
Oh, and I think Disciple take half the time to call back, if necessary.