My Favorite Idol Became My Little Sister by Kawai Roh — Ongoing
Also known as Oshi ga Imouto Ni Narimashite.
Ichika Kojima is a high schooler obsessed with the idol "Kanon", beautiful and popular with her (girl) underclassmen, Ichika really only spends her time as an idol fan; her life changes when one day her father remarries and she gets a step-sister, none other than her beloved "little sister of humanity" Kanon, or rather, Akane?!
This Hyper Yuri Love Comedy begins now☆!