Octaman

A principled yet funding-driven scientist who leads the expedition, driven by groundbreaking discoveries but frustrated by the lack of financial support. He pushes to present findings in America and secures outside funding, even if it means compromise. His ambition drives the plot as he confronts ethical tensions around exploiting the creature for profit.

Co-leader and steady researcher who navigates escalating danger alongside Torres. She helps coordinate defense during Octaman attacks and participates in trapping and capturing the creature, balancing scientific curiosity with a concern for her crew.

A humanoid octopus mutant capable of moving on land, terrorizing the expedition and nearby villagers. It is eventually captured but revives after a storm and remains a deadly threat, complicating the scientists’ mission and prompting dramatic confrontations.

A young Indigenous man from the nearby village who knows local legends of a half-man, half-sea-serpent. He guides the scientists to the lake and spurs them on during the pursuit, providing cultural context and a bridge between the locals and the researchers.

A circus promoter willing to exploit the mutated creature for his act. He represents the opportunistic side of science's pursuit, pushing for capture and display despite the danger to the crew and the ethical concerns raised by Torres and Lowry.