In Which Ep Eren Become Titan

This is the critical difference. Eren does not "transform" out of a desire to live. He transforms out of a desire to destroy .

The discovery that Eren is the Titan inside the nape changes the genre of Attack on Titan overnight. The show pivots from "hopeless survival horror" to "political thriller with monsters." in which ep eren become titan

In this episode, Eren is swallowed by a Titan while saving his friend Armin. Initially, he is presumed dead. However, inside the Titan's stomach, he refuses to give up. His intense will to live and desire to kill Titans triggers his power for the first time, causing him to transform into a Titan from within the other Titan's body, bursting out and saving himself and Armin. This is the critical difference