The Jenova Project was first started when the remains of an ancient named Jenova was found. Not much was really known about the Ancients, so Shinra scientists decided to study her. What they found was that if you inject Jenova's cells into a human, they augment their strength and magic power. But there were also unforseen side effects. Some of the subjects mutated. Dr. Hojo is curently the head scientist in The Jenova Project. He is the mastermind behind Soldier, Shinra's elite soldiers whose strength was augmented through injection of Jenova cells. Soldier's finest warrior was Sephiroth.
You're going to fight four different versions of Jenova. I'm not sure if these creatures were imperfect clones of the original or what. A few things are certain, though. They look very strange and they're not hard to defeat. Your first actual encounter with Jenova is when you are on your way to rescue Aeris from the Shinra Building early in the game. You see her headless body in a special cell labeled "Jenova." When you return to the cell moments later, she's gone.
Jenova-BIRTH: You fight her when you're on the boat going from Junon to Costa Del Sol. She's not too tough. Just hit her with the summons you have and limit breaks. She'll stop some of your characters occasionally, but it doesn't last long and she fights pretty slowly anyway. She doesn't have any definite weaknesses, though.
Jenova-LIFE: You fight her after the event with Sephiroth in the City of the Ancients. This one's a bit tougher than the last. Make sure that someone equips the Water Ring you just got because all of her attacks are water-based. Levithan + Elemental on someone's armor will help, too. Just don't USE Leviathan on her. She's weak against Earth attacks, so put Earth + Elemental on someone's weapon (Cloud's a good choice) and use Titan on her. Be careful about using spells on her besides summons, though, because she casts Reflect on herself. Beware if she casts Aqualung because it deals a lot of damage to whomever isn't protected against water.
Jenova-DEATH: You fight her after you get to the Whirlwind Maze by the Northern Cave, which is after you get out of Ice Gate Glacier. She doesn't have any weak spots, but she's also not that tough. Use the newly acquired Bahamut, Alexander, and Neo Bahamut summons on her.
Jenova-SYNTHESIS: By this point, you should have Knights of the Round, so just cast it once and kill her. If not, cast the most powerful summons you have. You need to cast spells that damage everything because of the two tentacles in front. Overall, she's still not that tough.
Age: ???
Hometown: ???
Occupation: Soldier
Weapon: Masamune
Sephiroth was the ultimate soldier created by The Jenova Project. He was a distinguished leader and respected member of Soldier until he came upon a libray hidden away in the basment of the Shinra Mansion in Nibelheim. When he found out his true nature and about The Promised Land, he became obsessed with finding it. He figured that the easiest way to reach the promised land would be to create a wound in the planet so large that massive amounts of Mako Energy would be released to heal it. He then planned to use that Mako Energy to enter The Promised Land. His plan was to use Black Materia to summon a great meteor which would collide with the planent causing the massive wound. Your goal in Final Fantasy VII is to stop Sephiroth at all costs.
Where you find him: Your first actual encounter with Sephiroth is when you reach Nibelheim, though Cloud, as a member of Soldier, worked under him. He's in the library where he first discovered information about The Promised Land. All he'll do is throw the Destruct materia at you, so make sure and pick it up.
Subsequent Encounters: Your next encounter with him will be the Temple of the Ancients. Again, you won't have to fight him, but you will have to fight the Red Dragon and the Evil Wall. You run into him again in the City of the Ancients, where he flees but leaves behind Jenova-LIFE for you to fight. When you reach the Northern Caves, he'll have you fight Jenova-DEATH, then get ready for a LONG event. Your next encounter is the last one. Once the barrier to the Northern Cave is destroyed, you can enter it and find him. Just before you fight him, he'll throw the last Jenova at you, Jenova-SYNTHESIS. Then be prepared to fight two different forms of Sephiroth.
Bizarro Sephiroth: He has five different parts, which you have to defeat individually. You'll also be able to split your characters into three seperate parties. If your first wave doesn't make it, your second wave can go in. But, honestly, going to yout second wave probably isn't needed. First, if you have Knights of the Round, skip strategy and just unleash the Knights on him. One casting and an additional hit should do it. Otherwise, he's not that hard anyway.
Seraph Sephiroth: Due to a bad Japanese to English translation in one of the strategy guides, you may know this form as Safer Sephiroth, but it's really Seraph since he looks like an angel. Seraph Sephiroth utilizes what has to the be the most beautiful, yet horrifying enemy attack I've ever seen in any RPG. It's called Super Nova. I won't give away what it looks like, but let's just say you haven't seen ANYTHING like it. Anyway, he's tougher than Bizarro Sephiroth. If you have Knights of the Round and just want to get the game over with, pelt him with about 2-3 castings of it and that's it. If you're going for strategy, make sure you've got Megalixirs because Super Nova hits everyone for a lot of damage. I highly suggest using Big Guard at the beginning of the battle, then Shield and Regen on everyone. Then pelt him with Summons. Make sure you've got Destruct on (you know, the materia he threw at you?). Well throw it right back at him by using DeBarrier to destory his barriers. Watch out, though because he casts DeSpell, which will get rid of your Shield, Regen, and Big Guard (Haste + MBarrier + Barrier). He also uses a status changing atack, so make sure everyone has Ribbons. If you just have Knights of the Round, this battle is TOO easy. For a REAL challenge, try fighting Emerald Weapon and Ruby Weapon. But at least resist to urge to kick his ass across the Life Stream until he's cast Super Nova on you at least once because it's a VERY nifty-looking attack.
Now that you've defeated Sephiroth, sit back and watch the beautiful graphics in the ending.