The Demon King's Growth Plan

An invitation letter, a different world with [Gift], and a thousand-year war between gods and demons, started a legendary game life. As a member of the Demon King candidates, Chen Xiao and the other 35 candidates are facing a crusade from 108 brave men, and there is also the risk of internal strife. However, why are the heroes in this world high school students summoned from the island country? Could it be that too many brave men have gone dark recently, so the threshold for saving the world has begun to lower?