Episode 12, the story about Otorimonogatari, contains the story Nadeko Medusa. Nadeko said this:
Favorite big brother: Koyomi Oniichan
In Love with: Araragi Koyomi
why she said it differently? Does it mean that she consider Araragi as two different person? Because in Monogatari Series Second Season she turn out to be a
yandere, and want to kill Araragi, the man that she love.