Much more unhinged than he initially appears with a very twisted view of romance. States that he likes her most when she is hating him, and would actually prefer that she not develop romantic feelings for him.

Hence the roughly translated title: To The Hateful You, I Like You.

Why he has become the way he is - that is to say volatile, unpredictable, abusive and irredeemably vulgar in his expression of 'love' yet oddly sweet to Mikoto - is assumed to be revealed later throughout the story.