Nayuta Moriyama is a vice president of the Misumaru Middle School student government, an honor student known for strict adherence to rules and protocols. She is the daughter of the priest at the local Tenmo Shrine, placing her within a lineage tied to the town's cultural, protective traditions and its hidden responsibilities.

Her demeanor is serious and stoic; she struggles to express emotions outwardly and strongly prefers self-reliance, resisting dependence on others even under pressure. This discipline defines her approach to student council duties. Despite her reserve, she reveals a competitive streak during school events like sports festivals. Nayuta possesses a slender frame, long black hair usually in high twintails, and brown eyes. Her attire typically includes a distinctive black choker necklace with an attached coin, a long-sleeved red and white shirt, blue pants, and white shoes.

Like other council members, Nayuta wields telekinetic abilities, such as psychically locking and unlocking doors to control access. Her most significant power is transforming into the Shingu, a towering guardian defending Earth against extraterrestrial threats. As the central protector in Tenmo's ancient defense system, the Shingu uses environmental elements like water to form its body during battles.

Nayuta experiences gradual emotional growth, particularly through her relationship with classmate Hajime Murata. Initially emotionally restrained, she faces vulnerability during personal crises, including psychological withdrawal. Her interactions with Hajime foster mutual reliance, deepening into a romantic connection where his support helps her overcome challenges. This journey contrasts with her ancestral resemblance to Lady Momoe, who faced similar struggles with a figure analogous to Muryou Subaru.

Within the student council, Nayuta works alongside the hot-tempered Kyouichi Moriguchi and the composed president Hachiyou Tsumori. Though her rigidity occasionally causes conflict, the group coordinates closely to manage threats and uphold their guardianship. Her familial role at Tenmo Shrine intertwines personal obligations with the town's interstellar diplomatic functions.

Guardianship of the Shingu imposes personal burdens, framing her abilities as both a responsibility and a weight. Her journey navigates reconciling duty with emerging individuality, confronting legacy expectations tied to her family's shrine duties and the Shingu's defensive role. This progression reflects the theme where protecting the community requires balancing collective duty with personal growth.