Anime Crossover: Suoh Yuki is actually my sister?

+++“Who will you choose, her or me? I'm your first little sister!” — Kasugano Sora “Sen is Mashiro’s owner.” — Shiina Mashiro “I am your only choice!” — Suo Yuki Female protagonists included: Mygo, Saekano, Lonely Rock, Sakura-sou, My Neighbor Girlfriend Who Whispers Her True Feelings in Russian, A Certain Sora, Oregairu, The Quintessential Quintuplets, Rascal Does Not Dream of Bunny Girl Senpai, Girls' Bunny (GBC), etc...