Mushoku Tensei takes place in a fantasy world based on the sword and sorcery genre. The story revolves around an unnamed Japanese NEET who dies and reincarnates in the fantasy world as Rudeus Greyrat. He retains all the knowledge from his previous life and vows to make the best out of his second life without any regrets.

Main characters

Before his reincarnation, he was a plump 34-year-old Japanese NEET who became a recluse following his high school persecution and dropout after being tormented by an upperclassman; although his family, friends and school peers encouraged him to return to school, he refused and pushed them all away. When his parents passed away twenty years later, he refused to attend their funeral, as a result, he was disowned by his siblings and kicked out of the family home, making him homeless; while wandering the streets, he spotted a truck headed towards a group of high school students crossing the street at high speed and ran over to save them; causing the truck to hit and kill him in the process. After his reincarnation, he discards his past identity, and works hard to make his new life as Rudeus Greyrat more meaningful. As such, he adopts a gentleman persona, though his past life's perversion sometimes emerges and scares those around him. Since he retains his intelligence, Rudeus was able to start magic training at age 3, and learn how to cast magic without chanting. Due to this training, he has an abnormally large mana capacity. Because his magic teacher, Roxy Migurdia, helped him to overcome his fear of the outside world, he admires her and ties his accomplishments to her. During his spare time, Rudeus makes figurines to enhance his earth magic, which has become his main offensive magic.

A mage from the Migurd tribe known for their telepathy, blue hair, youthful appearance, and longevity. She leaves her village due to feelings of isolation: she is not telepathic, but Migurds prefer to use telepathy for communication. Unable to make a stable living as an adventurer, she becomes a traveling tutor and eventually becomes Rudeus' teacher. After the teleportation incident, Roxy helps Paul search the world for survivors. She later becomes Rudeus' second wife.

An elf who is Rudeus' childhood friend and longtime crush. Bullied as a child, she was helped by Rudeus. Rudeus then teaches her magic when she asked him to after she witnessed him helping her with his magic. Rudeus' influence helped her learn how to cast magic without chanting. She later becomes Rudeus' girlfriend and first wife.

A noble girl and a second cousin of Rudeus. She is a girl with a short temper but has potential in the Sword-God style. During her journey with Rudeus to return home following the teleportation incident, she grows to love Rudeus but gets worried after seeing how Rudeus was defeated by Orsted and nearly died as a result of her not being strong enough to protect Rudeus with her sword skills. She then leaves Rudeus on a journey to further enhance her sword fighting power. After reuniting with Rudeus, she became his third wife.

Greyrat family

Rudeus' father. He discarded his noble lineage due to its restrictive lifestyles and became a proficient swordsman skilled in all three sword styles: Sword-God, Water-God, and North-God style. He is described as a playboy and an adventurer with sharp intuition. Following the teleportation incident and unable to find his family, Paul falls into a depression and drowns his sorrows in alcohol until his reunion with Rudeus.

Paul's first wife and Rudeus' mother. She also left her noble home due to the restrictive lifestyle, and she sought to become an adventurer with her skills in healing magic. Paul saves her from people attempting to take advantage of her and she falls in love with him. When Lilia becomes pregnant with Paul's child, Rudeus convinces her to forgive them.

Originally Paul's classmate in a swordsman dojo. A crippling injury forces her to leave her position as a princess guard. She becomes a maid to Paul and Zenith. She later has an affair with Paul and becomes pregnant. After working through the revelation with the family, she is taken in as Paul's second wife and becomes closer friends with Zenith. Rudeus' behavior as an infant scared her, though she swears her loyalty to him after he helps her to reconcile with Zenith.

Zenith's daughter and Rudeus' younger sister. She was with Paul after the teleportation incident and loved him dearly. When she saw a violent argument break out between Rudeus and Paul, she grew scared of the former and began to resent him.

Lilia's daughter and Rudeus' younger half-sister. From her mother's teachings, Aisha takes it upon herself to manage Rudeus' housework. She is exceptionally talented and intelligent but dedicates herself to housework instead of furthering her skills.

Rudeus' first child, and Sylphiette's first child and only daughter. At the age of three, she began to receive the same training as Rudy when she was a child, learning magic and swordsmanship. She always thought that because of her father was a great genius, she didn't have any expectations for the late-blooming children, so she have been working hard to get her father's praise and approval.

Rudeus' second child, and Roxy's first daughter. The way she grew up with her hair tied behind her back is very similar to her mother, to the extent that even her father once mistook her and hugged her from behind. Unlike Roxy, she has the telepathic ability of the Migurd tribe to talk to her. According to Rifujin na Magonote, it is heavily implied Lara is the key to defeat Hitogami in the future.

Rudeus' third child, and Eris' first child and only son. He inherits his late grandfather's dead-ringing personality due to his similar hairstyle, sexual perversion, and interest of swordsmanship. When visiting the Holy Kingdom of Milis, he sneaked out with Lily and Sieghart for an adventure and was almost kidnapped when he got lost on the trip until his half-aunt Aisha helped Leo to arrive in time to protect them. In Redundant Reincarnation Volume 3 (nicknamed "Jobless Red Carpet"), he genuinely developed a romantic relationship with Aisha at the time they were caught by Rudeus and leads to family crisis, causing them to elope elsewhere; Roxy was the only one who regretted their incident and eventually lets them go. The following year, he and Aisha are living in a cottage, where the latter was pregnant as a result of their relationship. After their sword fight and genuine love, Rudeus decided to forgive them with several conditions, one of which was that Ars had to continue his education and had to be old enough to propose to Aisha, along with their newborn child Leroy needs to stay in the household as Aisha departs to look forward in an uncertain future. Since several years later, Ars finally met Aisha again. He seems to have grown into a handsome and mature man and now he is ready to propose to Aisha as his wife. As a result of controversy from readers as well as a violation of their terms of service caused by this decision, Rifujin na Magonote ultimately decided to retain it in the light novel onwards.

Rudeus' fourth child, and Sylphiette's second child and only son. Due to his emerald green hair which is similar to previous antagonist "Laplace", Rudeus and Sylphiette felt anxious about his hair after the birth. However, Rudeus faced Perugius with the will to defend Sieghart to the end even if he was the reincarnation of Laplace. Perugius asked Rudeus to take Sieghart to the Sky Continent to complete a trial that allows Rudeus to dispel his doubts.

Rudeus' fifth child, and Roxy's second daughter. She wanted to be a researcher despite her ordinary fencing and magic skills through her mother.

Rudeus' sixth and youngest child, and Eris' second child and only daughter. Out of all Rudeus' children, she is extremely attached to her father and even spoiled by him, her mothers or her siblings.

Fangs of the Black Wolf

A powerful swords-woman from a beast race and a member of the Dedoldia tribe, she has the epithet of Sword King and is a former member of Paul and Zenith's old party, Fangs of the Black Wolf. She is also the aunt of Linia Dedoldia. Ghislaine is employed as the Eris' family bodyguard; however, because she never learned to read and write, she was susceptible to scams until Rudeus taught her literacy and magic, including spells to enhance her abilities.

; Mallorie Rodak (English) An elf. She was Paul's former comrade and was part of Roxy's search party to help her look for Rudeus after his disappearance. She is also found to be Sylphiette's grandmother.

Geese is a Demon Tribe member and an S-ranked adventurer in the thief role of the group.

He is the dwarf magician of the party with an affinity for Water and Wind magic. He is the 37th out of 51 siblings.

Boreas Greyrat Family

He is the strict and outspoken landlord of Fittoa and the grandfather of Eris.

She is the sophisticated and protective mother of Eris and Philip's wife.

He is the most easy-going member of the family and the father of Eris.

Beast Tribe

Gustav is the chieftain of the Beast Tribe and Ghislaine's father.

Gyes is Ghislaine's impulsive older brother and the father of Linia and Minitona.

Minitona is the cheerful little sister of Linia.

Migurd Tribe

Roxy's youthful father, who is only capable of speaking telepathically.

Roxy's youthful mother, who is only capable of speaking telepathically.

Demon Tribe

The demon empress known for her demon powers and the ability to bestow others with power. She is engaged to Badigadi.

Badigadi is a boisterous demon at the university and Kishirika's betrothed. He is the younger brother of Atoferatofe.

Atoferatofe is a demon who bestows strength. She is the older sister of Badigadi.

Moore is a stern and clever demon general serving Atoferatofe Rybak.

Ranoa University of Magic

A human born with unique abilities. His ability grants him superhuman strength and endurance. Since his youth, he had a fondness for dolls.

The grandson to the pope of . He is a Special Student in the school due to his talents. and

The beast-girl candidates to become the leader of their village. They are from the beast race with cat and dog characteristics, respectively. Linia is also Ghislaine's niece.

One of the Special Students. A genius in her own right, she never shows up to class due to her research.

A princess of the Asura kingdom who competes with her brother to the right to succeed the throne. Ariel is wise charismatic but vents her stress out through sadistic acts. She and her bodyguards develop a strong friendship during their time together. Ariel intends to become the queen to honor the people who died for her.

He is Rudeus' cousin and the personal knight to princess Ariel Anemoi Asura on the university grounds.

A young dwarf girl whom Zanoba purchased to train her to help him create figurines.

The recently promoted vice-principal of the Ranoa Magic University, and Roxy's teacher.

Counter Arrow

She is the caring Vice leader of Counter Arrow, an adventurer party that helps Rudeus after he parts ways with Eris.

An impulsive young member of Counter Arrow, who eventually takes interest in Rudeus.

A kind and experienced magician of Counter Arrow specialized in Fire and Earth magic.

The healer of Counter Arrow.

A Warrior Mage and a frontliner of the Counter Arrow party.

Sword Sanctuary

He is the head master of the Sword Sanctuary and Sword God, ranked 6th on the Seven Great Powers, who takes Eris as an apprentice due to their shared desire to beat Orsted at his former student Ghislaine's behest. He is also Nina's father.

She is initially a proud and conceited young student under her father, who becomes the rival and later, the friend of Eris. Her romantic interest is fellow student Gino.