Is Sephiroth actually Jenova?

[Bloodline666]

He even kills President Shinra because the Shinra were poking their noses into finding the promised land as well. Since when did he ever get there? I don't know where you're getting this from.

I can answer that question by going a bit deeper into the meaning of the Promised Land.

I could be mistaken, but according to the information provided by the UOG (as well as in-game dialogue from Aerith, herself), the Promised Land is not any one particular place set in stone that you can easily find on a map, but rather, it is something unique to each individual that brings a person supreme happiness. Thus, the term "Promised Land" is open to interpretation among the cast of FFVII; therefore, the "Promised Land" Aerith ultimately sought is not the same as the "Promised Land" Sephiroth and the Shinra were seeking (which is reiterated in "Maiden Who Travels The Planet"); basically, there's two known interpretations of the Promised Land in-game. Here's how this is possible.

Sephiroth sought the "Promised Land" to rule the Planet, as did Shinra, but they both had different means to do so. Sephiroth sought to use the Black Materia to call Meteor to injure the Planet to crisis levels, and steal the spiritual energy gathered to heal the wound for himself, while Shinra sought to build a larger version of Midgar with Mako Reactors draining even more spiritual energy than the ones currently active, and in the process, increasing their profits; obviously, such an area would have to be abundant in the Planet's spiritual energy. Sephiroth and the Shinra's interpretation of the "Promised Land" ended up being the Northern Cave.

The Cetra, on the other hand, sought the Promised Land to achieve supreme happiness by virtue of the peaceful sleep of eternal rest. Essentially, this means that the Promised Land could only be reached through death. There's only one place someone goes after death; the Lifestream. Which tells me one thing; the Cetra believe that the Lifestream, itself, is the Promised Land.

By falling into the Lifestream via the Nibelheim Mako Reactor AND ending up encased in a shell of materia in the Northern Cave, Sephiroth ended up finding BOTH known interpretations of the Promised Land.