chapter 18 who is this person

When Dakota Fitzroy forced her to marry him with a knife, although Azariah Irving thought Urdr Fitzroy was just his younger sister, he did not want to become a couple with her. But that was just due to physical reasons. Azariah Irving didn't want Urdr Fitzroy to marry him and become a widow. Now that his health was getting better, he naturally chose Urdr Fitzroy as his first choice.

Why are the two of them childhood sweethearts who grew up naked and know each other well? Secondly,...