Frieda Reiss

This woman appears in Eren's and Historia's dreams.

Appearance
When he dreams of her, Eren first mistakes her for Historia, which shows that they must look similar.

Story
She appears in Eren's dream, with him seeing her from her own perspective, while she looks into a mirror. . In Historia's dream however, she actually interacts with the woman. She teaches Historia how to read and tells her to be become a kind person. But when Historia claims that she wants to be like the woman, she refuses this suggestion and the proceeds to manipulate her memory, telling Historia to forget about her, until Historia sees her again.

Memory manipulation
She is shown to be able to manipulate the memories of a person, when she manipulated Historia's memories