Vincent Valentine

In the Mansion in Nibelheim, go to the safe upstairs. Enter the following:
right 36
left 10
right 59
right 97
You cannot pass any of these and go back. When the safe opens fight the boss then open the door in the basement hallway. Talk to Vincent twice then leave, he will join you.














Yuffie Kisaragi
In the forest near fort condor engage in a battle till you find a mysterious ninja. Beat her then respond to her like so:
"not interested"
"petrified..."
"wait a second"
"that's right"
"let's hurry on"
If done properly, you can now select Yuffie as a Character.