There's idolized little sisters, protective older sisters, cousins raised as sisters, step-sisters, and adopted sisters. The last few are supposed to i loved koi kaze, yosuga no sora, oreimo (not really much romance but still ) & wasn't overly fond of da capo. i just like the whole brother sister thing i just prefer it non blood related if possible =/. Boku wa Imouto ni Koi wo Suru This one has both a manga and an ova, the ova.