Amat Roy serves as the vice captain of the spaceship Slayle, a vessel operated by the Azatos Empire on a mission to survey Earth. At twenty-one years old, he is a young but serious-minded officer whose physical appearance includes unique features such as a small horn-like bump on his head and cat-like pupils, traits he shares with his longtime companion, Liza Luna. His hair is blue and cut to ear length, and his eyes are grey.

Possessing a logical, calm, and serious personality, Amat acts as a grounding presence aboard the Slayle. He is known for his rational thinking and flexibility, making decisions without being overly concerned with the opinions of others. This serious nature can sometimes lead him to entertain odd or overly pragmatic conclusions, but his primary function within the crew is that of a voice of reason. He is often described as the last bastion of rationality on a ship that is rapidly succumbing to an overwhelming fascination with Earth's creatures.

Amat shares a deep, sibling-like bond with Liza Luna, having grown up alongside her. He places complete trust in her judgments and actions, a loyalty that initially leads him astray. Based on Liza's fragmented and misunderstood reports, Amat becomes convinced that cats are dangerous and terrifying monsters that pose a threat to Earth's inhabitants, which makes him extremely cautious about the planet's wildlife. His role in the story is defined by this initial misconception and his subsequent resistance to the wave of adoration for cute animals that sweeps through the rest of the crew. While his comrades, from the captain down to the survey teams, quickly fall under the spell of cats and dogs, Amat remains one of the few members who has never encountered a real Earth animal in person.

As the narrative progresses, Amat's steadfast logic is gradually tested. Although he continues to view the crew's obsession with skepticism, he finds himself increasingly interested in cat-themed everyday items that Liza brings back to the ship, suggesting that his own resolve may be weakening. A significant development in his character arc involves his relationship with Mecha Yozora, a cyborg created in the image of a cat named Yozora. Amat becomes the caretaker of this artificial feline, whose quirky and often illogical behavior leads Amat to form a series of humorous and inaccurate conclusions about what real cats are like. While Amat has strong logical thinking and leadership abilities befitting his rank as vice captain, his primary challenge is an internal one: reconciling his rational worldview with the inexplicable, powerful charm of Earth's cutest inhabitants.