Zack Davis

Zack Davis is a human Directorate agent who is one of the first people Sienna makes contact with. He and his partner Kurt Hannegan are sent to retrieve Sienna when the Directorate learns she exists and that Wolfe is after her.

In Alone Zack is described as a little taller than Sienna (who is 5'4"). In later books he is described as about six feet tall. Initially Sienna thinks he is in his late 20s, but Zack says he is a couple of years out of college so he is probably around 24 years old in Alone.