Yusagi stressed the importance of leading with one's morality and the idea of negative effects or impacts on other people in the making of the character as Naofumi is accused of sex abuse.

[3] Anime director Takao Abo aimed to portray him as the weakest of the summoned heroes due to his relative lack of aid when fighting.

[6] After Kametz announced that he was taking a leave of absence from voice acting after being diagnosed with stage IV colon cancer, which ultimately led to his death on June 9, 2022,[7][8] Stephen Fu replaced him for the ongoing seasons.

Originally an open minded person, he becomes cynical and distrustful of others due to being looked down by his fellow heroes, subjected to religious prejudice from citizens, and being robbed and falsely accused of attempted rape by Malty.

Generally reluctant to trust strangers, often asking to be paid upfront or using slave curses to prevent lying, he tries his best to live up to the expectations of those who have placed their faith in him or treat him as an equal.

After defeating Kyo and ending the threat of the Spirit Tortoise (the Cal Mira Wave in the anime), Naofumi is given control of Raphtalia's hometown.

He soon plans to rebuild and make a makeshift army to fight against the Waves and remaining Guardian Beasts, purchasing the original displaced inhabitants and other slaves to repopulate.

Although Naofumi has a slow start because of the public's perception of him and being unable to attack enemies directly, he is still able to keep up with his fellow heroes and even outshine them due to unlocking a wide variety of shields that boost his allies and passive skills.

In a review of the first light novel, Anime News Network found Naofumi's hatred towards society for accusing him of a crime as too much to follow him, based on some actions, most notably buying Raphtalia as a slave.

[14] In a following review, ANN praised the author's handling of Naofumi's quirks as "His cynicism helps to drive the plot forward, and more importantly, it shows that he thinks about his actions and their consequences more than the other Heroes do".

Manga.Tokyo praised Naofumi's character arc in the anime due to how decides to stay to protect his friends rather than returning to his own world as he thanks Raphtalia for his constant aid, something which made the reviewer look forward to them in form of a romantic relationship in a future season.

Timothy Donohoo of Comic Book Resources heavily criticized how Naofumi comes across as an "overpowered protagonist who's seemingly never wrong" and for the "socially contentious undertones", noting that "the series has gotten its fair share of well deserved flak".

[23] FandomSpot author R. Romero ranked him as the 10th best Isekai protagonist in anime as, despite criticizing his disdain towards women, he becomes likable in the story thanks to his character arc.