Board Thread:Manga/@comment-32563139-20170717125925/@comment-30905663-20190527173053

Semi Spoilers for chapters 110-117

Zachley purposed that Zeke might have some ability to control Eren but he didn't elaborate on it much. I think that at some point Zeke slipped Eren his CNS fluid and has since been able to  manipulated his memories to nudge his motives in the right direction.