The Pretender (Animorphs #23)
To Tobias, no one is who they seem. He has just heard a reading of his father's last will and testament. That's how he found out who his father really was: the Andalite Prince Elfangor! Tobias is stunned, but can't show it. Because Visser Three is watching his every move.
Author: K.A. Applegate
Publisher: Scholastic Paperbacks
Release Date: 1998-11-01