As children, Azusa and Yuzuru were engaged by their parents. Yuzuru told Azusa that he loved her and was happy to be marrying her, and then he went back to his home in Tokyo.
Years later, as teenagers, Azusa's mother dies mysteriously and she announces that she's going to go to Tokyo to meet her bethroded, Yuzuru. Yuzuru hasn't seen Azusa in many years and just assumes she's probably become interested in some other guy. Yuzuru's girlfriend, Satomi, doubts that Azusa will have forgotten him so easily.
Satomi's assumption is correct, Azusa flirts and clings to Yuzuru at all times. One night, some thugs attempt to attack Azusa and she flies into a rage and kills them. She remembers doing the same thing when she was a small girl. Azusa becomes very jealous of Satomi and uses her demonic powers in an attempt to kill her, but not before Yuzuru realizes what's going on. Yuzuru has no other choice but to kill her with an arrow through the heart.
The idea of a "Head Family" (将来本家の入り婿に) is mentioned many times in this story. The characters that make up this phrase are worth examining as well. Of these you have "in the future" 将来 "head family/main family branch" 本家 and then "man who marries a woman and takes her name" 入り婿 (irimuko).
The idea of Yuzuru marrying Azusa and taking her name is known as mukoyōshi (婿養子). This is a centuries old tradition that is still in practice today. As Azusa has no male siblings and is of a higher socio-economic class than Yuzuru, the idea of a mukoyōshi even among cousins seems like a natural choice for her.
Kyudo (弓道) is the Japanese martial art of archery. All kyudo archers hold the bow in their left hand and draw the string with their right. The string is drawn until it passes their ear. For the most practiced archers, when the string is released the bow will spin in their hand so that the string stops at the outer forearm. This is seen often with Kikyo and Kagome in Inuyasha.
The glove that Yuzuru wears while firing an arrow is known as a yugake (弽) and comes in three or four fingered variety. The thumb of the glove may be hard or soft depending on the archers preference.
The creatures that Azusa controls most closely resemble gaki (餓鬼) or hungry ghosts. These yokai suffer to always crave sustenance and yet never be satisfied no matter how much or what they eat.
