In Rewrite, Sakuya, Chihaya's butler, is nothing but antagonistic towards the protagonist Kotarou from the moment they first meet. He calls him insulting names and is generally just a bit of an asshole. It later turns out that both he and Chihaya are working for Gaia, the eco-terrorist group who want to destroy all human life
(and who ultimately succeed in the final episode of Season 1).
Then, around Episode 8 or so, he randomly shows up in the magic forest and saves Kotarou's life. He announces he's now working with Kotarou and friends against Gaia, offers to train Kotarou, and becomes considerably less antagonistic towards him. Absolutely no explanation is given for this, and to me it seemed to come completely out of left-field.
What prompted Sakuya to change sides like that so suddenly? I think Chihaya may have already defected by this point, but surely that can't be the only reason?