Welcome to Demon-School, Iruma-kun

Someone had done something to change Ameri's personality! She's usually confident and stern, but now, she's now meek and dainty and the student council can't hide the fact that they're not sure how to handle the situation. While all this confusion is going on, Ronove Romiere, the president of the Disciplinary Battler comes to try to steal Ameri's position. He proposes a dissolution election against the student council. Who is behind the changes in Ameri? What will be the result of the election?