[Son of Sephiroth]

Emerald = underwater one

Ruby = in the desert

ultima = flying around

Diamond = Midgar attacker

Sapphire is killed in a cutscene when the Junon cannon fires in it's face.

Now. Ruby is hardest to beat technically, but it can also be glitched using a simple system. 4 materia, are needed for it to work as a base, the rest should be just be filled with magic plus materia.

1. character should be alive. He/she should be equipped with:
Hp absorb=Knights of the round and Magicc counter = mime.

Now, cast KOTR once and leave. Everytime Cloud is struck he will mime, casting KOTR again, which in turn will restore all his health. He should also have a ribbon and as many magic plusses to maximise damadge. The same can work on Emerald, but you need the underwater materia as well to remove the counter.