Clement Rage
Pro Adventurer
I thought JENOVA and Sephy were basically more a partnership than either being in control. 'I'm good at messing with people's memories, you're good at killing stuff, let's collaborate to achieve our goals.'
It's not clear whether this is true. He needed someone else to get the black materia, and the other clones are not very functional. It's also possible he was following Cloud to find Aeris in the City of the Ancients.
In truth the whole plan to achieve the black materia and cast meteor does not require Cloud's presence at all. Sephiroth/Jenova could have left Cloud rotting in his cell back at SHinra HQ, and the plan would have gone on just fine.
It's not clear whether this is true. He needed someone else to get the black materia, and the other clones are not very functional. It's also possible he was following Cloud to find Aeris in the City of the Ancients.