User blog comment:NickFusi0n/A Theory on The Coordinate and The Wall Titans/@comment-3074300-20140524172812/@comment-86.88.104.182-20140524205941

Im not thinking this is true, My theory is that the serum that Grisha injected into his son actually turned him into a normal titan. With Grisha already being a titan shifter with the coordinate power, we know that if a titan eats a titan shifter, the titan becomes a titan shifter with the original shifter's powers (as seen with Ymir) So im thinking that Eren ate his own father to get the coordinate powers. It also explains why eren scribbled something about his dad in titan form and then lost control, he remembered it partially and lost control about him eating his own father.