Who is the narrator?

20,000 Leagues Under the Sea by Jules Verne is narrated in the first person by the character of Pierre Aronnax. Throughout the narration, we tag along with Aronnax as he is first taken under the charm of the charismatic Captain Nemo in spite of his normally scientific and objective nature. We understand firsthand his wonder at how the Nautilus functions and hear directly about the terror he feels throughout their adventure. Over the course of the story, Aronnax shows the reader his slowly dawning realization that Captain Nemo is not the man he thought he was at first, but rather much more mysterious and nefarious.
Aronnax's narration is limited to his own perspective. We often see only what Aronnax is allowed to see by Nemo. At the end of the story, after the destruction of the Nautius, Aronnax tells the readers that he is reporting the story exactly as he experienced it without any revisions.

Not a single fact has been omitted, not the slightest detail exaggerated. It is the faithful narration of an incredible expedition. (2.23.3)