User blog comment:Eddienam/Chapter 53 mystery/@comment-76.31.149.155-20140109032232/@comment-179280-20140110063125

@Neo Because of what Eren remembers Grisha telling him when Verman fires the cannon at them, being that "this power will help him recover Wall Maria". And now, Eren writing "my father" and "to me" while being transformed. Taking only the first part will make us think that it may be both, while the second implies that the injection gave him the Titan Shifting. Now, it's also possible that the posession of the Coordinate grants Titan Shifting abilities.