
He was more rough to everyone before he met Tia cause his parents cared about his brother more than him(in chapter 74).But he become a bit gentle after meeting with Tia cause Tia was a caring girl with a warn heart.He got the caring he wanted from her.So he treasures her,way too much like overprotective or hating other boys who approach Tia.
Of course,he isn't so nice (yendere) to others except Tia but I don't think he will become a sadist.And counting the times they hug and their tea times together ...etc are because he is a genius so that he could remeber.You know,how a genius's way of thinking is different from normal people.
Oof I can only ship carsien and tia in my dreams cuz I know that she won't end up with him... (/TДT)/