Kazuma: He is a 17-year-old Japanese teenager who became a dead man and was later reincarnated in a fantasy world. After joining the Adventurer's Guild in the fantasy world, he was initially assigned as a merchant due to his good luck attribute, however he requested to be assigned as an adventurer which, despite being one of the lowest ranking classes, allows him to learn various skills from other classes. With his powers, Kazuma learns basic skills such as stealing, archery, monster detection, and basic magic. Kazuma's main skill is "Steal", which allows him to steal a random item from his opponent, but to his surprise, he can only steal women's underwear.

Aqua: Also known as "The Goddess of Parties", she is a water goddess who judges the souls of young people who died in Japan to send them to a new RPG-like world, until Kazuma takes her with him. She is a simple and energetic girl who likes to receive bows for her stats and gets excited easily. She is too conceited, so she complains about the simple life she has as an adventurer on more than one occasion, although deep down she likes it. After joining the adventurer's guild in the fantasy world, as an Archpriest and a goddess, she is powerful against demons and undead, as well as being able to revive recently dead people and purify water reserves. Instead of learning skills that would benefit her party, she spends most of her skill points on learning pranks for her companions. Despite usually bringing trouble with her, Aqua is very kind-hearted, but tends to bring more harm than good in her attempts to make things better. He has several debts with the Adventurer's Guild due to damage to the city and spending on food and liquor.

Megumin: She is an Archmage who is a descendant of the Crimson Demon race; powerful humanoids who possess black hair and red eyes, as well as carrying chūnibyō characteristics. A very dramatic 14-year-old girl who speaks the Japanese dialect in an ancient style and wears an eyepatch despite having two normal eyes. As Darkness, despite being an Archmage, she can only use the spell "Explosion". Known as the most powerful offensive spell in the world, it gets rid of anything in a large area, but she can only use it once a day, as it drains almost all of her mana immediately after using it, causing her to be unable to move a muscle (forcing Kazuma to carry her most of the time). Megumin refuses to learn any other spells despite Kazuma's insistence.

Darkness: Another adventurer who has trouble finding a team like Megumin, Darkness is a 19-year-old paladin who possesses powerful offense and defense, but lacks the precision to land her attacks. She has great stamina and is able to withstand many hits, which is possibly due to her having a fetish for damage done to her; she dreams of taking serious hits from monsters or marrying an abusive husband. Despite her ambiguous fetish, she has a noble heart, and cares deeply about people and being a good role model for others; though her masochistic tendencies tend to get in the way of that. It is later revealed that she is a beautiful noblewoman from the influential Dustiness family, and that she became a paladin to defy her father's wishes.