Especially these two, from book 2 onwards, keep reappearing as key persons who would set the course of each story (though they are the ones most unaware of that fact).
特にこの二人は2巻以降も（本人達が一番自覚が無いにもかかわらず）それぞれの話の方向性を決定付けるキーパーソンとして登場し続ける。