Ymir assists Eren Jaeger and his allies for most of Attack on Titan's first two seasons; however, in a shocking twist, she departs from their side to help Reiner and Bertholdt return home.

The revelation that Mr. Kruger from Marley was Eren Yeager in disguise was one of the most surprising twists in Attack on Titan. Falco is completely fooled, but Reiner instantly recognizes him.