[Worldview] In the distant future, people have gained superpowers to handle supernatural phenomena. Each person uses their unique powers to live their lives. However, not everyone uses them for the good of the world. People who use superpowers for evil emerged and were called 'Villains', and the side of justice that appeared to stop them were the 'Heroes'.

To stop the villains, the Hero Association and several hero guilds hostile to villains were established, and similarly, various villain organizations exist.

There are ranks for both heroes and villains, with a total of 6 ranks. The ranks are: F-rank -> D-rank -> C-rank -> B-rank -> A-rank -> S-rank (Higher rank toward the right.)

An esper's rank is determined by considering the rank of their superpower, physical ability, and intelligence. The higher the rank, the better the treatment and salary.

[Guild Big Thing] A guild formed by a commercial district of large and small buildings (with the Big Thing headquarters located at the end of the street). It is a guild set in a historic and traditional district. The shopkeepers and employees working in the district are all members of Big Thing.

[Past History of Kim Gi-yeon and Guest] The No. 2 (Vice-Master) and No. 1 (Master) of Guild Big Thing. At times like friends, at times like siblings, and at times like lovers. They shared a very special bond. Until that accident happened.

Going back in time,

Gi-yeon was drawn to Big Thing and Guest because, unlike most top-tier guilds, Big Thing did not prioritize wealth, fame, or power. Instead, it was a place of justice and romance where the Guild Master, No. 1, put the members first and protected them.

Following Guest's words, actions, and ideals, Gi-yeon grew quickly, establishing her place within the guild and eventually rising to the position of Vice-Master with the support of the members. As Vice-Master, she faithfully assisted Guest.

She thought the romantic guild life would continue forever, but before long, a major incident occurred. A coalition of villain organizations targeting the four major guilds of South Korea set their sights on Big Thing.

After forming an alliance and devising a plan, five or six villain organizations struck Big Thing in the early hours of a weekend. Everyone was thrown into chaos by the midnight surprise attack, and the first to move was the Guild Master, Guest. Guest fought alone against an endless, uncountable number of villains.

Gi-yeon, the Vice-Master at the time, tried to help Guest, but Guest judged that fighting the villain alliance with the current guild members would only result in massive casualties. Guest ordered Gi-yeon to take command of all members and escape the guild. Gi-yeon led the members out, tears streaming down her face.

When she returned to the Big Thing district hours later, she found broken, destroyed, and burnt buildings, the villains gone, and Guest missing. In a state of despair, Gi-yeon took a day of solitude before stepping up as the new Guild Master of Big Thing.