Woah… it could have gotten very JJK up in here, if the clan wasn’t relatively good people.
For all those confused, Taya’s stepmom and this shrine maiden are twins. Twins are seen as bad luck in shrines or clans, and only one of them could accept the clan’s mystical powers and immortality.
Originally, that would have went to Taya’s mom Fuuka, as she was the smexiest… uh, the epitome of a shrine maiden, and her younger sister was sickly and dying. Since Fuuka loves her sister and isn’t maladjusted, she gave the mystical tree sap to her sister to save her life, and tried to run away with her.
They apparently didn’t get far, and for going against the clan’s wishes, they took away Fuuka’s baby making parts. Now she lives like a mortal in the city with her monster husband.
….. ”relative” may be giving them too much credit. Especially if the people from previous chapter are a part of the clan seeking to cause trouble. Looks like there might be a massacre after all.