A girl from the Crimson Demon Clan, which has produced many excellent mages. She usually speaks in a polite, gender-neutral tone, but her language becomes rough when she's angry, and she sometimes uses strange phrases like "yum-yum." In her inner monologues, she speaks like a boy. Her signature move is "Explosion." She is the daughter of Hyoizaburo and Yuiyui.

Originally an ordinary high school student living in a rural Japanese town, he was a shut-in who rarely attended school. However, he tries to take responsibility for his actions as much as possible. Consequently, he usually spends his time cleaning up after his companions' messes.

The Goddess of Water who guides humans who die young. She is a beautiful girl with blue eyes and long blue hair. As the Goddess of Water, she can purify any liquid—seawater, hot spring water, boiling water—into fresh water. Her weapon is a staff.

A high-ranking Crusader. Combining her father's sturdy body with her mother's strong magic resistance, she possesses enough defensive power to withstand even Megumin's Explosion magic, the strongest attack known to humanity. However, she is also a massive pervert.

Megumin's father. Despite his calm demeanor and a personality prone to flipping over the dinner table, he deeply loves Megumin and Komekko. His profession is Arch Wizard.

Megumin's mother. Her profession is Arch Wizard. She started a family with Hyoizaburo, a magic item crafter, and had two daughters. Because the magic items her husband creates are nothing but bizarre junk, they don't sell, leaving the family as the poorest in the Crimson Demon Village.

Megumin's younger sister, seven years her junior. When she first appeared, Aqua called her a "tiny Megumin" because she looks so much like her sister. Her personality is also almost identical to Megumin's: she is extremely independent, never listens to others, and is strong-willed and aggressive. She is also very sharp-witted, making her a handful even for Megumin. Because the family is poor, she is always hungry and is a wild child with a gluttonous streak who will try to eat anything edible.