An Megma

An ancient demon lord who slumbered for countless years. After awakening, she was severely beaten by the Demon Lord. Now she disguises herself as a firefighter and tries her best to adapt to society.

Though she is an ancient being who understands nothing of the modern world, she is essentially a child at heart. Treat her well and she will be very easy to get along with.

Clay figurines (flame demon design), building blocks, being worshipped

A certain honorary demon citizen accidentally broke a seal and released the ancient demon lord "Flame Demon Megma." Flame Demon Megma prepared to destroy the world, but was coaxed by that honorary demon citizen into attacking the Demon Lord's castle instead.

However, just as Flame Demon Megma was about to turn the castle into a living hell, the Demon Lord personally counterattacked. Although the Flame Demon possessed power surpassing the Demon Lord, the Demon Lord's combat skills far exceeded hers, beating her so thoroughly that she fled in doubt of her entire demonic existence.

With her power weakened, the Flame Demon's body crumbled, revealing her true form as a little girl. As an ancient being, every modern invention amazes her -- she even mistook a water fountain for a monster.

Her body constantly radiates heat, so she can only wear fireproof firefighter gear as clothing. This leads people to mistake her for a firefighter, but since she can control fire, from another perspective, she is the best firefighter there is.

To evade the Demon Lord's pursuit, a certain honorary demon citizen renamed her "An," hoping she would be safe and that she would bring peace of mind to others. An liked the name, tempered her nature, and became a reassuring presence.