Frankenstein Narrator:

First Person (Central Narrators): Robert Walton; Victor Frankenstein; the monster.

This story is told through the frame story of letters written by Walton to his sister. So ultimately, it is all his point of view. But within that frame, Victor tells him his own story. Deeper still, the monster relates to Frankenstein his own experience. So ultimately we have the monster’s story as told by Victor as encapsulated by Walton’s story. So it is a story within a story within a story.