I bolton, good work here.

Protagonist: Young (as you suggest), the outsider who best represents the audience experience. Also, as you note, he’s the character with…

I bolton, good work here. The movie is a challenge per the concept of five primary character archetypes because there are so few characters. While acknowledging that archetypes are tools, not rules, here’s my take.

Protagonist: Young (as you suggest), the outsider who best represents the audience experience. Also, as you note, he’s the character with the biggest transformation arc.

Trickster: Old. At first a kind of mentor figure as he knows his way around the island. Yes, he’s not terribly friendly, however, over time, he and Young develop a kinship. Evolves into an enemy by the end, so a shapeshifter.

Attractor: As you note, the Mermaid.

Mentor: While Old dons that mask, what about the island itself? By being forced to live separated from the ‘normal’ world, Young is compelled to confront his shadow self, and although a negative journey for him (he ends up being pecked to death by the seagull), it does represent his psychological fate of dealing with the actions of his past and the dark aspect of his psyche.

Nemesis: Seagull. The personification of his shadow. It haunts him and ultimately eats him up.

What do you think about that take?