Natsumi Hinata is a human teenage girl and one of the central figures in the Keroro series. She is the older sister of Fuyuki Hinata and the daughter of Aki Hinata. She lives with her family in Tokyo, where she attends school. Natsumi was the first person to discover Sergeant Keroro hiding in her brother’s bedroom, setting off the long series of encounters with the frog-like alien visitors. She is physically athletic and notably strong, excelling in sports and often taking on physical confrontations without hesitation. Her short temper is a defining trait; she can be fierce and aggressive when angered, frequently calling Keroro a stupid frog and assigning him house chores as a form of discipline. Despite this, Natsumi is also kind, vivacious, and brave. She cares deeply for her family and, over time, develops a protective fondness for the Keroro Platoon members, treating them as a kind of surrogate family. At school, she is popular due to her strength and straightforward personality, though in her earlier years she was known as Devil Summer for her fiery nature. She has a more vulnerable side, especially around Mutsumi Saburo, on whom she has a crush, and she enjoys listening to his radio show. Natsumi is also sensitive about things that creep her out, such as slugs, and loves baked sweet potatoes. She is initially suspicious of the aliens, but gradually accepts their presence and becomes a key figure in the Hinata household, often acting as the de facto commander of the platoon when needed. Her rivalry with Keroro is a constant source of comedy, yet there are moments of genuine care between them. A notable device created by Kururu is a neck brace that transforms her into a powerful fighter, allowing her to contribute in dangerous situations. Throughout the story, Natsumi matures from a hot-headed girl into a more responsible and rounded individual, balancing her strength with a growing sense of compassion. She maintains close friendships with Koyuki Azumaya and others, and the relationship with Giroro, who harbors romantic feelings for her, hints at a deeper emotional layer. Her role is that of a grounded human figure who both challenges and supports the alien invaders, serving as a source of stability and direct action within the narrative.