User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-177.42.160.74-20180115065353/@comment-175.139.25.169-20180115083952

I would think they will be permanent residents kuroka is officially in the harem, and from EX we know ley fay has a son with Issei so she is also in the harem just not officially, plus ley fay will be attending kuoh middle school so she would stay there as well