In fiction, one common and generic way to refer to well-drawn, realistic characters is to call them “round.” As in:

…characters as described by the course of their development in a work of literature. Flat characters are two-dimensional in that they are relatively uncomplicated and do not change throughout the course of a work. By contrast, round characters are complex and undergo development, sometimes sufficiently to surprise the reader.

2009. Encyclopædia Britannica Online.