Naofumi Iwatani [1].

Naofumi is a young man in his 20s, with a slim build and a tall stature. He has short, slightly unkempt black hair. He often wears a furrowed brow and his features are rather sharp. His eyes are emerald green. He wears barbarian armor (made by Erhard), and always carries his Legendary Shield. According to his own comments, his armor resembles that of a bandit leader.

At first, Naofumi is shown to be a positive and friendly young man, although somewhat clumsy. He seems to see the world with hope, although he is somewhat naive and lacks cultural knowledge, comparing the landscape around the Melromarc Kingdom to an advertisement for a travel agency. However, following the betrayal he suffered at the hands of Malty S. Melromarc and being accused of abusing her, losing his credibility as a hero, the respect and trust people place in him changes his way of being, becoming distrustful and cynical, to the point of sometimes being rude to others. Prepared to receive betrayal from anyone, he decides to live only to defeat the waves of calamity that terrified the world, and with it, to be returned to the world he came from. It is after he meets Raphtalia, and begins to live with her, that his personality returns, at least in part, to what it was; still distrustful, but kind to the young woman and to people in need, willing to help in exchange for favors within his means. However, part of his anger and resentment remain, manifesting itself when he uses his cursed array. When carried away by his fury, Naofumi is shown to be ruthless, even enjoying destroying and killing his adversaries, considering the rest of the world as his enemy. It was during his confrontation with the Zombie Dragon that he displayed this personality, taking care from that moment on to not fall into an abyss from which he cannot return.

Thanks to the bond he forms with Raphtalia, Filo, and Melty Q Melromarc, Naofumi slowly feels like he's found people he can trust. The bond he has with his comrades grows deep and unconditional, with Naoumi caring for them and even willing to give his life to save them. He will not forgive anyone who threatens or hurts his comrades, no matter who it is, as demonstrated by openly threatening King Aultcray Melromarc XXXII, implying that if he tries to lay a finger on his comrades, he will regret being born and become their enemy. For their part, his comrades also care greatly for him, as when Naofumi succumbs to the Shield of Rage and accidentally hurts Raphtalia, she pretends that her injuries do not hurt her so he will not feel guilty about what happened, even going so far as to put the mark of enslavement back on herself so Naofumi will regain her trust in her and not waver in her loyalty. Unlike the other Legendary Heroes, Naofumi sees the world they were summoned to as real and not as a video game, so he is constantly exasperated when he sees that they do not take seriously the consequences of their actions or the abuse of power they usually commit, such as when Ren Amaki killed a dragon and instead of getting rid of the body he leaves it in the place where he killed it, causing that due to its processing it will begin to affect the environment and the people of the nearest town to spread a virus caused by the putrefaction of his body, or when Motoyasu Kitamura naively gave a village a seed so that it would supposedly make plants grow and improve their vegetation when in reality it only caused the emergence of wild plants that took the villagers hostage.

After buying the village of Lurolona, Naofumi adopted Filo and Raphtalia, thus creating his own family, but while Naofumi was happy in his little paradise, Motoyasu could barely survive. He had no money and the little money he got he spent on food and water. He could not afford an inn, so he slept on the streets, barely surviving on random jobs here and there. And one night while wandering through the forest Motoyasu fainted from hunger in front of a river near Lurolona and Raphtalia found him and took him to Naofumi who took him in to Lurolona putting him to work mainly in the village's fields. Motoyasu was happy since at least he had a place to sleep and had a job to eat, and every day he gave his all to help out in Lurolona, both in the fields and in monster hunts although Motoyasu was not very good at combat, and one night while hunting with Naofumi Motoyasu almost died due to a snake monster but was saved by Naofumi which caused Motoyasu to see Naofumi as a savior, a guardian angel who watches over those under his command which led to Motoyasu seeing Naofumi as the most perfect man that exists, existed and will ever exist in the world, and what began as a feeling of admiration on the part of Motoyasu slowly turned into a love that bordered on idolatry towards Naofumi on Motoyasu's part.

Naofumi was born the firstborn of his parents, having a younger brother. As he grew up, he was spoiled by his parents, leaving his brother somewhat aside. Thus, over time, he leaned towards Otaku activities, although his parents gave up trying with him, focusing on his brother, to ensure him a future. However, the pressure was too much for him, becoming spoiled with them and even dyeing his hair. Naofumi intervened and managed to make his brother change his attitude, winning the affection of his parents, who began to give him 10,000 yen a month, allowing him to live a more comfortable life as a university student. Naofumi was once a university student before being summoned to the Kingdom of Melromarc . After being betrayed by Malty Melromarc , he transformed his optimistic and cheerful personality into a dark and cynical one, although retaining some of the kindness of his former self. Due to the incident with Malty, he had a slow start to his adventure, being somewhat behind the other heroes, however he has managed to keep up with them, even overshadowing them. Among the heroes themselves, he has been the only one to learn to read and write the Melromarc language, as he was not given a crystal ball to increase his magical abilities, having to learn from books alongside Raphtalia. He is also the only one of them who understands that he is in a real world and not in a game. Having started his adventure practically alone, he learned to make medicine, as well as to collect materials, which he uses as barter, and later, to sell them for a profit.