Yuu/MC has Decided to stay longer in the Devildom, as she has enjoyed her time with the brothers and her friends, but then a new exchange student showed up, and the brothers quickly replaced her. So, Yuu asked Diavolo to all her to bring a relative. How will they handle a deity, who doesn't take to kindly to the way her sister has been treated? What happens when they fall for her. "Touch her at all, and I'll end you where you stand."