So basically Zeke caught his half-brother's still-living head, which enabled them to contact the progenitor titan Ymir living in the earth who influences the memories
of her subjects throughout time.
So are these visions, or are they actually altering events in subtle fashions by permeating the consciousness of others?
If we're going for an Evangelion mind-screw ending, can Reiner be the only one left alive? Because that would be hilarious.