Final Fantasy VII

Converging Fates
A Ranma 1/2/Neon Genesis Evangelion/Slayers/Final Fantasy VI/Final Fantasy VII/Xenogears crossover. When an experiment in teleportation goes awry, it accidentally displaces several people from parallel worlds. Including a nameless entity, capable of possessing bodies at will, and feeding on its life energy. When it begins to use the people of Earth as a food source, it's left to the displaced heroes to do something about it.