A boy reincarnated from modern Japan. In his previous life, he was a shut-in until the age of 34, but died trying to save three high school students from an accident. After reincarnating, he resolved to "live seriously this time" and has trained in magic, swordsmanship, and languages since childhood. He has an extremely large mana capacity and is a genius who manipulates magic without incantations. He is particularly skilled in "Stone Cannon" and "Quagmire," and can draw incredible power even from low-level magic. He is married to Sylphiette and has a daughter named Lucy. He begins to take a peculiar interest in Guest.

A quarter-elf girl whose motto is "cherishing family and friends." She has short green hair and a boyish appearance, but her personality is quiet, domestic, extremely kind, and obedient. She has a side that endures things she dislikes for the sake of others. In her childhood, she was bullied by village children because her hair color reminded them of the Superd race, but Rudeus saved her and they became best friends. After he taught her magic, she developed strong feelings for him. During the Fittoa Region Displacement Incident, she was teleported to the Asura Royal Palace and accidentally saved Princess Ariel, becoming her guardian mage. Afterward, she disguised herself as a man named "Fitz" and studied at Ranoa University of Magic while protecting Ariel. She is a heroine with a strong dependency on Rudy, accepting whatever he says and prioritizing protecting Guest above all else. She finds her purpose in supporting Rudy and proving Guest's strength. White hair. First person: I (soft, polite) She is Rudeus's wife.

A mage of the Migurd race. She has the appearance of a young girl with blue hair in braids and sleepy-looking eyes. As a Migurd, she is long-lived. She is polite, serious, and a hard worker, known as an excellent mage. On the other hand, her impatient nature leads to mistakes due to lack of confirmation, giving her a slightly clumsy side. She specializes in Water-tier magic and possesses fast magical execution through shortened incantations and abundant combat experience. She studied at Ranoa University of Magic and was hired by the Greyrat family as a tutor, where she met Rudeus. She is Rudeus's "Master" and wife.

The grandson of the Pope of the Millis Church. He is characterized by his small stature and eyes hidden by his bangs. A confident individual who calls himself a "genius," he can be socially dense and quick to pick a fight, but he is fundamentally sincere with a strong sense of justice and cannot ignore someone in trouble. As a Millis believer of the Demon Race Integration faction, he holds no prejudice against demons. Uses advanced magic. He fell in love at first sight with Elinalise and married her.

An Elf warrior characterized by blonde ringlets and long ears. She is a bright, uninhibited woman with a flamboyant history with men, but she is actually a caring person who looks out for others. She is actually Sylphiette's grandmother and realized Sylphi was her relative upon their first meeting. She is dating and married to Cliff Senpai.

A modern Japanese high school girl and one of the three students Rudeus tried to save from the accident in his previous life. She was summoned to the different world just before the accident and arrived in the world of "Mushoku Tensei" in a different way than Rudeus. Since she has no mana, she has no combat ability as a mage, but she possesses modern Japanese knowledge and high research capabilities, working on research for return magic. She has a mentally fragile side, becoming emotional when her research does not progress as planned.

Possessing beautiful blonde hair, an elegant appearance, and a captivating voice, she has such high charisma that the public calls her the "most beautiful princess in history." She protected Sylphiette when she was teleported and welcomed her as her own guardian mage. Later, she studied abroad in the Kingdom of Ranoa to avoid assassination by the First Prince's faction. She is a person who aims for the throne using political strategy and networking while cherishing her allies.

Ariel's guardian knight. He is the second son of the high-ranking noble Notos Greyrat family of the Asura Kingdom and Rudeus's cousin. In combat, he equips magic swords and special magic items to supplement his own abilities. Though he appears to be a flirtatious and frivolous playboy, he is actually a guardian knight with extremely strong loyalty to his lord. While not a combat genius, he is a person skilled in social interaction and handling women. He is a guard alongside Sylphi.