Natsuki Naoko and Kenichi

Despite having an evil gaze that makes her look like she is in a bad mood, Naoko is actually the type of person that doesn't really think of anything, and her compassion toward others is generally off the mark and irrelevant; however, she always prioritizes her son Subaru. Both Kenichi and Subaru agree that she is the most slow-witted person in the world at least on the surface, but later in Subaru's trial, Naoko shows she is more perceptive then she appears. Like her husband, she is a mayonnaise lover.

At some point, Naoko married Kenichi and had a son with him; Subaru. Naoko would take notice of how her son idolized his father and wanted to be like him. However, after this proved to be impossible, he went through a downward spiral that ultimately resulted in him becoming a shut-in. While the self-hating Subaru wanted his parents to reprimand him, the couple saw that their son was just going through something and instead subtly encouraged him to go back to school every day.

According to the author, after Subaru went missing (was transported to Lugunica), a police investigation was launched but ended up empty-handed. As a result, Kenichi and Naoko now spend their days praying for their son's safety.

Son Subaru: Born and raised in Japan, Natsuki Subaru is a young Asian teenage boy. He stands at a height of 172 cm with an athletic physique which he maintains both prior to and during his summoning to Lugunica.

He inherited a shared mix of physical traits from both of his parents; his medium-length thick black hair bore a striking resemblance to his father as well as his face shape, while his black (brown in the anime) sanpaku eyes which have small irises that made the whites of his eyes stand out, were inherited from his mother although some people find them intimidating, with the exception of some individuals who like them, namely Emilia. Just like his father, Subaru has quite an athletic build, as back in Japan, he was raised as an athlete by his father. Despite his shut-in nature later on, he nevertheless continued to train himself to maintain his physique.

Subaru's main attire throughout the early parts of the series is his cheap, athletic-theme outfit he was summoned in. The ensemble consists of deep-grey tracksuit bottoms with an orange stripe down the side, black sneakers with vibrant orange laces and soles, and a black t-shirt. Additionally, Subaru has with it a zipped-up white tracksuit jacket with a stand up collar, deep-grey sleeves with an orange line running down their sides and orange cuffs, and deep-grey shoulders. On the left breast of the jacket is a black brand symbol that is reminiscent of the letter N.