To answer a few questions you guys may have, if you have any more i'll add em onto here:

1. how old is wannie?

i'm not too sure about hybrid ages and the way that works, but she's still in puppyhood, a relatively young girl. in relation to human age she's probably at the maturity level of a 5/6 year old? 

*quick note: seungwan may speak in simple sentences for a child of that age, but that's because she doesn't speak alot. she doesn't really need it. joohyun and her have a very special bond outside of conventional speech, so it doesn't really matter.*

2. how big/small is she? 

hybrid seungwannie in this story is only slightly smaller than the real seungwan. in reality, seungwan is the shortest in red velvet, even shorter than irene, so yeah.

3. how is joohyun able to pick seungwan up like a child?

it's easy for her, reallly. because seungwan is slightly smaller than her, but mainly because joohyun's a vampire. and vampire joohyun has no concept of weakness. not gonna lie, i kinda built the physical traits of her character on a mix of traditional vampires and twilight vampires (that's where the super strength comes from).