A character who is familiar and unsurprising seems comfortable, believable — but not particularly interesting. A character who is unfamiliar and strange is at once attractive and repulsive, making the reader a little curious and a little afraid. We may be drawn into the story, curious to learn more, yet we will also feel a tingle of suspense, that tension that comes from the earliest stages of fear, the uncertainty of not knowing what this person will do, not knowing if we’re in danger or not.