Tsukihi Araragi Friends

Karen is the sister of Koyomi and Tsukihi Araragi in the -Monogatari franchise.

Koyomi Araragi is the main character of Bakemonogatari a story of a high school student who is attacked by a vampire and ends up meeting all sorts of mythical creatures, based on a light novel series written by Nisio Isin and illustrated by Taiwanese illustrator Vofan.

Nadeko is a childhood friend of Koyomi's sister and was cursed by a jealous classmates before being saved by Koyomi.