My dark mana killed her

His son is happy. 

Duke Balthier Sanguine sighs. If his son is happy, he should let this go. 

If he objects, his son will do something worse.

Eli is about to turn away and leave the study when his father calls for him.

"Wait for a moment." Duke Balthier walks to his safe. "I have something to give you."

What could it be? He already got the letter. Eli looks over his shoulder and finds his father placing a small wooden box on the table. Curious about the box, Eli walks back to the desk.

"Your mother would have wanted you to have it." Duke Balthier opens the box. In the box, there is a black long earring and a white ivory bangle with ancient symbols.

In their kingdom, there is an important ritual in a traditional engagement ceremony. The groom puts on a bangle on the bride. The bridge will put the earring on the groom's ear. 

This bangle and the earring are a set.