Gokinjo JK Isezaki-san wa Isekaigaeri no Daiseijo

One day, the 30-year-old office worker, Koutarou Matsunaga, is stabbed by a thug while protecting Seina Isezaki, a high school girl who lives nearby. And just as Matsunaga's life is about to end, he is revived from near-fatal wounds by Seina's power. But his relief is short-lived, as Matsunaga's newly awakened power suddenly goes out of control, and the two are transferred to another world. One of swords and magic, where Seina once lived as a Great Saintess.