The psychotic nemesis of everyone, Sephiroth was generally disliked by everyone on DDD - With the exception of Colette and the other friendlier members.

Yunalesca used him for mainly selfish reasons after her one-night stand with Kadaj and encountering him when Kadaj transformed. Under the guise of Sephiroth reminding her of her husband she gave Sephiroth free use of the Farplane, without thinking of the consequences and later to try and create a new Sin.

His reign of terror ended when, after spreading Geostigma through the Farplane with Yunalesca's aid, killing Rufus Shinra, and nearly killing Vyse Dyne, he was put upon by a great many members of DDD, (taxxied by Demyx) and was subsequently defeated after a last ditch effort to become the next Sin.

It was later revealed that Yunalesca, who faded away with her energy gone, had been mind-controlling an avatar of JENOVA by manipulating pyreflies. They created only an essence of Sephiroth- her motives however were unclear. However, the true Sephiroth was banished back to Kadaj's mind, to drive him crazy.

Sephiroth has currently taken control of Kadaj, suppressing him and seemingly erasing Kadaj from existence. From there, Sephiroth made a deal with Yunalesca if she could not bring back Kadaj, she would be bound in servtitude. However when he stabbed Yunalesca in the chest, it gave Kadaj enough emotion to break through.

Soon though, Yunalesca seperated Kadaj and Sephiroth with a glove that Ichigo gave her.

Sample Quotes:

Sephiroth: I aim to use the dead planet as a vessel with which to travel between worlds. I do not require the company of others.

Demyx: ...that is the most messed up Gummi Ship ever.