Enjoying the role of the older brother of a girl I love dearly.

He has an important girl. A girl he loves very much. She is his stepsister, and the two of them were not real siblings. At that time, she was so young that she didn't know this fact. Before it's revealed that she's his stepsister with no blood relation and he's seen as a romantic interest and distances are taken, he intends to suppress his feelings and return to being a normal sibling. But until then, he had no intention of hiding his affection for the girl he loves behind the mask of a siscon. (Currently being posted on other sites)