The first is set in the Persian Wars period and stars Latro, a mercenary who has amnesia at the end of each day and he has to record the important events so he can remember why he is heading to a particular temple to be healed by a goddess. It certainly isn't full of those "make-believe" creatures.

The latter is a dying earth-type novel set a million or more years into the future. Unlike Latro, Severian claims to have eidetic memory. Like the former, some of the fun is in reading for the inconsistencies and sleights-of-hand that Severian engages in. Very dense, but ultimately rewarding work, with all sorts of references to gnostic, Greek, and early Christian mythos.