Board Thread:Manga/@comment-31940900-20160907231313/@comment-30069705-20161002021507

Yes. That too. Somehow, he could manage to tap into the full power of the Coordinate, even gaining all the memories and knowledge of all previous holders and controlling titans at will and everything (and more if there is anything else the Coordinate has to offer). It would greatly compliment his other titan powers, which he could gain even more of still (like be able to form a titan that's bigger than any other so far, his super titan form in the anime becoming canon even in the manga, and any other special titan powers that could be a big help). Maybe he could also do more training to hone his fighting skills and 3DM Gear prowess while he's at it, and maybe Levi and Mikasa could make great practicing partners, but they may not have enough time for that, so I won't hold my breath on that.

As for what would trigger him to gain full use of the Coordinate's power, well, the first time he activated it, it was spontaneous because he was all worked up and got caught up in the moment between things like everyone being in real peril of dying with him not being able to do anything about it, Reiner and Bertolt with their betrayal, Hannes dying at the hands of the very titan that killed his mother, etc.

Maybe the next time he uses it, something like that could happen again, but only it's even more critical and pushes him even further. Maybe more of his comrades die this time, including former enemies who just become allies again (Annie and Reiner immediately come to mind), and maybe even Zeke could play a role in it (since he's almost certainly related to Eren in some way, like maybe his older half brother, and he may not be as bad as previously thought after all, and may even be one of their allies towards the end, especially considering he was even talking about saving Eren). I don't know. Anything's possible.