As Chapter 3 is still airing and is relatively new, there haven't been much Chapter 3 backgrounders of worthy note as of yet. However, a highlighted backgrounder from Chapter 3 was the "Girl with a high ponytail", who made her debut in "Spring Unsprung". Her backgrounder design shows that the franchise has developed much more detail in creating the backgrounders, and have even given her a speaking role.
Girl with a high ponytail
She has a thick and curly high ponytail clipped up with a gold clip. She has a black, short furry blouse over her fishnetted top. She wears a plain white skirt and pale mint stockings with stripes, as well as black platforms. She accessorizes with a feather bracelet and several gold bangles, with crystallized earrings and a headpiece. She also has a speaking part, in 'Spring Unsprung' and 'Dragon Games'.