[cyberdemon]

Originally Posted by Kanon

Spoiler for Ending:

The thing is, Cloud believes Aerith is alive, while she is in fact dead. That's more than enough to break him down. Sephiroth can just have him believe he's the one who showed him visions of Aerith while no one else could see her and he'll think he's crazy.

Tifa's case is interesting, because in Rebirth, Sephiroth does everything in his power to make Cloud distrust her and think she's an imposter, so his plan seems to be different than in the OG where he used her to confirm his lie.

Spoiler for Ending:

he knew Tifa could save Cloud like in OG. By making him distrust her, it could make it even harder for Cloud to piece himself together. He specifically targets these 2 because they were the main cause of his downfall in OG