Megumin is a young girl with shoulder-length dark brown hair (smooth black in light novel) and crimson-colored eyes. She wears a classical witch attire such as a black cloak with gold border, choker, wizard's hat, fingerless gloves, and carries a black staff. Though she jokingly claims that her eyepatch seals her immense power, she actually sees it as a stylish sense of fashion due to her chuunibyou tendencies.
She has fair skin and a light complexion. Unlike her rival Yunyun, who has a more developed body, Megumin seems to have a delicate under-developed figure, as Kazuma describes her figure as a "porcelain doll." Yuiyui also stated that all of their family members have thin bodies, but Megumin thinks that it's just because they lack nutrients because they hardly eat solid food.
Megumin is a straightforward girl who speaks in an old-style Japanese dialect. She can be very hyper and lively at times and has chuunibyou tendencies like the rest of the Crimson Demon villagers. She is very intelligent, but has very little self-control, especially when it comes to using Explosion magic. She has no problem wasting her spell on empty plains or abandoned castles, as long as she can use Explosion once a day.
After being harassed for days by Megumin's Explosion magic, Beldia was annoyed and called her a crazy-headed girl ("Girl with screws loose"). Much to Megumin's dismay, since the nickname describes her quite well, "crazy-headed girl" also became her official nickname in Axel. Kazuma stated that Megumin has the most common sense among the girls in the party, but considering her competition, it is not much of a compliment. Megumin also enjoys participating in (or starting) childish antics with Aqua or Darkness, and often acts over-dramatic to hype up the moods.
Megumin is generally calm and cheerful, but she can easily become aggressive when she feels slighted or challenged. Kazuma stated that she is magnanimous and cherishes her comrades more than anyone else. This is evident as she will become fiercely protective when others mock or try to hurt her allies. She also hates being treated like a child just because of her young appearance and becomes despondent when people call her a loli.
Because of her love for Explosion magic, Megumin will show great aversion to anything that she deems to be an imitation of such, or things she deems to be fakes and deviants to said Explosion magic, as shown with her reaction to Kazuma's recreation of dynamite.
While still attending school, Megumin would swindle food from Yunyun every day since her parents couldn't afford meals. Due to her exceptional academic performance, Megumin was able to graduate early. When she left to travel alone, Yunyun predicted she would be "at a loss due to a lack in the means of survival, begging a useless guy for a meal."
After traveling to Axel Town, she quickly gained a reputation as a crazy Explosion fanatic, thus parties refused to accept her before she met Kazuma and Aqua.
Explosion Magic: Megumin is absolutely obsessed with Explosion magic. She devotes all of her skill points into improving the power of her explosions, shortening her casting time, and being able to cast the spell without chanting out loud. However, the severe mana drain, combined with Megumin never using points to increase her mana, results in her always collapsing after casting and becoming completely immobile. Also, her refusal to learn any other magic makes her entirely dependent on allies after casting. This is especially notable because there are other known Arch Wizards who can use Explosion magic, can remain standing after casting, know at least one other skill, and can fight alone if necessary.
- "Megumin" is a Japanese nickname commonly given to girls named "Megumi," which means "blessing."
- Her name is presumably a pun on the KonoSuba title, as the "Shukufuku" translates to "Blessing," or "to bless."
- Megumin sends a portion of her savings back to her family each month, but avoids sending too much or else her father would waste it on making useless magic potions. In total, her personal earnings for the entire year have been less than 10 million eris.
- Due to her tendency to steal the final blow, along with the spotlight, Megumin receives the bulk of the experience points earned by each of the party's conquests, leading to her being the highest level in the party at around the mid-40s.
- She has a barcode birthmark on her butt.
- Her purse is full of shopping points cards and coupons, even after becoming a multi-millionaire.
- “Wahahahahaha! My name is Megumin, the number one mage of Axel! Come, you shall all become my experience points today!"