Fuminori Teshima 
An Archdemon’s Dilemma: How to Love Your Elf Bride: Volume 17 [EPUB ebook] 

The world is abuzz as centuries of hostilities between sorcerers and Angelic Knights have been brought to a screeching halt by the now-widespread knowledge of the relationship between Chastille and Barbatos—disregarding whether they admit to actually being in one.

Meanwhile, Zagan begins his research into how to destroy the Sacred Swords so that he can free the seraphs sealed within them. At the same time, faced with various challenges like Marchosios’s scheming and the demons’ arrival, he plays his next hand: to begin negotiations with the oldest living Archdemon, Forneus. And who better for the job of dealing with an idiosyncratic Archdemon than the brand-new couple, Shax and Kuroka?