In the game when cloud goes unconcious or falls asleep (e.g. when he falls through the church roof, when he sleeps at aeris' house, when he sleeps in the woman's house at junon, etc) who or what is the mysterious voice that appears as grey font on the black background?

I have thought of three possibilities.
1. Cloud's subconcious - his lack of memory is torturing him
2. It's sephirtoh inside his head, trying to control him
3. It's the same voice the clones hear that tell them to go to the reunion.

If anyone could clear this up it would be much appreciated. I've sussed this storyline apart from this factor.