Hero Summoning

 (召喚勇者) the term for the so called ancient ceremony. The number of summons is originally three heroes, but the recent ceremony summoned 4 heroes, one which isn't even a hero. Not everyone is hero, but there are rare instances like Mukoda's involvement. The ceremony is a taboo because it causes distortion of space and time, and if it fails, both worlds will collapse. Even if it is successful, it is impossible to send the heroes back to their original world in light of danger. The summoned heroes has an item box with no time lapse and has an overpowered status regardless of occupation, and comparatively high level of appraisal skill, and is able to understand languages of other countries.