McRory might be the narrator and protagonist but it’s Morgo here whose name is the serial’s title.
In my early research about the novel, before I actually read it, it sounded like Morgo was a Mowgli/Tarzan sort: a boy raised by beasts who becomes king of said beasts. Morgo’s actual origins are both more complicated and vaguer than that. Morgo was a young English boy prior to his life in the caves, so he knew “civilization” at one time. Once he came to caves he was adopted by the protomen and batmen in one of the lower caverns. Somehow he rose to become their king and leader. How that happened is left vague.