Yn Servopoulos is Tess' younger sister. She was only fifteen when the Cordyceps outbreak happened on September 26, 2003. Four almost five years into the outbreak, when she's nineteen, she and Tess meet two brothers, Joel and Tommy Miller. They team up with them and fight together until they reach the Boston QZ. Over the years, yn grows a crush on the eldest brother, Joel. But she hides her crush because, one, He's older than she is; Joel was 32 when the outbreak happened; she was only fifteen. That makes him seventeen years older than her. Now, that didn't really bother her much, at least not in this world. Joel was strong and fearless, or at least he seemed to be fearless. He knew how to take charge, and he protected the ones he cared about. The second thing was that yn was at least eight percent sure Joel and her sister were in some kind of relationship. Third of all, she was definitely sure the man hated her. What she failed to realize was that Joel did like her; he liked her more than he thought he should. She's younger than him. She was only a couple of years older than Sarah. Then there was the fact that she was Tess' sister. He considered Tess a friend. He's might go as far as to say she's best friend. They grew closer because of the similar trauma they suffered from the outbreak. He lost Sarah, and Tess lost both her husband and her little boy. He made it his mission to keep yn at a distance, not too distant, though. He still looked out for her and had the strong feeling to always protect her. And he never failed to feel angry or jealous when another man got too close. When twenty years into the outbreak they find themselves smuggling a fourteen year old girl out of the QZ to get her to a lab because she's immune and could be the key to a cure, they lose Tess on the way, leaving them to only have each other. Secrets come out, and feelings become confused and awkward.