A/N: I was really, really, really bored.
Once upon a time there was a ninja named Yuffie Kisaragi. She traveled all over the world making new friends (like policemen and angry mobs) and sharpening her ninja-fu skills to become next Lord of Wutai (they were sexist so there was no 'Lady' title). One day, a meteor decided to strike, and with the help of her inhumanly powerful friends, it went boom.
Of course, people decided to pair all of the party members up, and she ended up being paired with Vincent Valentine in many a fanfic and news article. Getting pissed off, she and Vincent went on a journey to defeat the evils of fandom, but then, unfortunately for her, she fell in love with the overly depressed gothic gunman. They turned him mortal. They got married.
Yuffie and Vincent, in the end, like Cid and Shera, hat exactly 2.9 children. They grew old together and died. Cloud and Tifa were married three years later after Tifa 'saved' him from a dead flower girls ghost with her big breasts and a gloved fist. As for all the others?
Well, they died too, even Red XIII, oh, excuse me, Nanaki, except he died 455 years later. Supposedly he had been the last of his kind, but he still found a mate and they had, exactly 4 cubs, for that is the way things are in the big liony cat race.
Sephiroth was sentenced to seven years jail time in the lifestream, after which he could do as he pleased. 500 years later, he distroyed the world with another meteor.
The end. Really.