Sai as Hanji Zoe (ハンジ・ゾエ?), she is a Squad Leader from the Scouting Legion. Hanji conducts research on Titans and, as such, is deeply interested in Eren Jaeger, who can turn into a Titan.
She is introduced as part of the group assigned to take Eren to his military hearing in front of the leaders of the military. She is present with the rest of the Scouting Legion as Levi beats up Eren and checks on his condition after the tribunal is over, noting that the gap where Eren lost his tooth earlier is disappearing quickly.
Although devastated by the loss of the test subjects, she moves forward with the experiments on Eren. When it turns out Eren cannot turn into a titan at will, Hanji is a little disheartened. However, seeing Eren's titan hand later on earned an overly-excited response, breaking the tension between Eren and the Special Operations Squad.
She discovered that Eren's titan powers are only awakened when he has a clear objective in mind, such as defending against the cannonball. She also theorized that this switch must have a good reason as well as being connected to the titan's nature.