The changeling
The changeling who has taken the form of Apollo's child symbolizes the way that many of the characters, including Apollo most significantly, change their personality and how they act over time. Like a changeling, Apollo changes who he is.
The troll
The troll that Apollo is forced to confront is a symbol of the ancient and oftentimes hidden threats that exist beyond the realm of modern society.
The mention of the island
The motif of the island represents the feeling of being cut off from what we know as familiar. In the story, it's a physical and psychological place of isolation, reflecting Apollo's emotional and mental detachment from reality and his journey into the unknown.
Apollo's broken glasses
Apollo's broken glasses, which often happen when he encounters dangerous beings like the troll, symbolize his inability to see things going on around him clearly.
Emma's depression
Emma's post-partum depression is symbolic of the struggles that many new mothers go through after giving birth. It also explains her actions and her decision to kill her child, who is later revealed to be a changeling. In that way, the depression changes who she is.
