Torikago Miko to Seiken no Kishi

In this country, there is a legend—a legend of the sacred sword, which has been a symbol of the nation for centuries. The knight chosen by the sword is known as the "Holy Knight," gaining extraordinary power and a life devoted to battle. Anne Duke, the youngest of a prestigious family of knights, fears wielding a sword unlike his brothers. One day, he meets Orietta, the newly appointed priestess of the sword.

(Source: Kadokawa, translated)