Oreimo: Kuroneko(2011)

Ore no Kouhai ga Konna ni Kawaii Wake ga Nai

OreKou follows the story of the light novels, set at the time when Kirino Kousaka leaves for America to undergo athletic training. While the OreImo anime series tells the story in Kirino's elder brother Kyousuke's point of view, OreKou focuses on Kuroneko's experiences as Ruri Gokou, a high school freshman who becomes Kyousuke's junior. While Kuroneko struggles in mingling with her new classmates, she tries to sort out her feelings for Kyousuke.

(Source: OreImo Wikia)

Note: Chapter count includes a Chapter Zero prologue and four additional bonus chapters.