pieck was born not being able to feel emotions. She would only be able to feel emotions if she found someone she loved. She became the cart titan very young. Pieck and zeke went to paradis to capture the founding titan and help reiner and bertholt.

when they started fighting the scouts she was in her cart titan form and zeke in his beast titan form throwing rocks at the scouts killing them

then she felt a jolt of emotion. She knew it was from one of the scouts. She now needed them…