The content of Re:zero Kara Hajimeru Isekai Seikatsu - Kenki Koiuta:
Rezero Kara Hajimeru Isekai Seikatsu Kenki Koiuta Manga : When a demon falls for an angel…
Long ago, a great war raged between the royal military forces of Lugnica and the demi-humans. A hero was born on that battlefield–the Sword Demon, Wilhelm Trias. This is the story of that legendary swordsman–and the woman he loved.