This is a fantasy oneshot.

Vampires: Taeyeon, Yoona, Hyoyeon & Sooyoung

Humans: Tiffany, Seohyun, Sunny, Yuri & Jessica

Relationships: Taeyeon & Tiffany  Seohyun & Sunny  Yuri & Jessica [daughter Yoona]  a little Hyoyeon & Sooyoung

Ages: Vampires: Taeyeon - 152 years  Hyoyeon - 98 years  Sooyoung - 70 years  Yoona - 2 weeks (Vampire years = the years you have been a vampire. Human years don't count.) Humans: Tiffany - 25(+11) years  Seohyun - 21(+43) years  Sunny - 23 years  Yuri - 23 years  Jessica - 25(+37) years. (The first number is the age they look to be, the (+) years are the years they haven't grown in aka they've drank vampire blood from time to time.) 

And yeah, this story breaks some laws of physics/common sense lol. Two females can have a child. Two humans can have a vampire child. A vampire and a human can have a child. Two vampires can not have a child. Vampires grow to adults and then stops. Humans stop growing and heals faster when drinking vampire blood. Vampires might too enjoy drinking vampire blood. Vampires die naturally at around 500 years of age. Vampires can't die from anything but age but can be very hurt by sunlight.

So live with that or don't read haha.