Still, Eren goes as far as challenging his friends—Armin, Mikasa, and others—into stopping him. In quite a tragic ending, Mikasa is the one to finally kill Eren and to stop the attack.

In Season 3 Episode 21, the previous Attack Titan, Eren Kruger, tells Grisha Yeager to complete his mission if he wants to save Mikasa and Armin before injecting him with the Titan spinal fluid ...