Nai was always Karoku's favorite… Karoku's 'special child'. The innocent lovable, older brother. Shi was Karoku's 'miracle child'. The more mature, distant younger sister. Both loved and adored Karoku, who they were with ever since they could remember. But it was not to last, using the clues left behind, they go on their journey to find him. (OCxGareki, other pairings possible)