Toaru Ouhi no Neyagoto ~Teishuku na Tsuma wa Ikani Shite Haranda ka~

Rick used to be a Knight and was fighting for his country for years until finally losing the war which also results in losing the country to another. Queen Sofia is wife of the current King and always worried about not being able to bear a child even after 15 years of marriage. As the successor problem arises, the King has to welcome a new concubine and it saddens Queen Sofia to the utmost. As prisoner of war, Rick is disowned by his own family after being released and disarmed. While thinking about his vague future ahead, Rick meets Tanya, the maid who used to serve his family before becoming personal maid of Queen Sofia. Tanya reveals that Rick is descendant of former King and gives him the duty to impregnate the Queen as it's necessary to preserve the old King's bloodline.