Cameron is a 30-year-old man who appears younger than his age. He initially struggles with blaming others for his problems but experiences significant personal growth throughout the novel. He arrives at Sowell Bay seeking to exploit a business scheme but instead finds an unexpected family network with Tova, Ethan, and others. Cameron's journey involves overcoming his flaws and ultimately becoming a more responsible and self-aware individual.

Marcellus is an octopus and one of the novel's narrators in *Remarkably Bright Creatures*. He is wise yet lonely, constrained by his life in the aquarium. Marcellus develops a unique friendship with Tova, recognizing their shared experiences of loneliness and the end of life. His interactions with Tova bring a sense of purpose to his life as he helps to connect her with others and add depth to the storyline.

Ethan is a relatively static character in the novel who plays an integral role in the lives of both Cameron and Tova. Originally from Scotland, his experiences of change, loss, and renewal contribute to his careful approach to love and friendship. Known for his inclination to involve himself in others' lives, he offers support and friendship to both Cameron and Tova, solidifying his place in their found community.