Board Thread:General Discussion/@comment-27043993-20160210162514/@comment-24908808-20160211220551

To further evaluate:

Dandere (ダンデレ?) A character that is portrayed as antisocial, but eventually changes to display their sweet, romantic, and loving soft side.

Kūdere (クーデレ?) A character archetype considered cold-hearted and indifferent, but not showing true colors.

Basically they have a cold shell to hide their soft insides.