Decided to add in exactly what happened between Firion and Sephiroth. The scene takes place not in Firion's storyline, but in Warrior's. It provides some more interesting insight to Sephiroth's character in this game, who seems to use his own special brand of mindscrew on our heroes.
Warrior comes in, saves Firion who looks to be winded, if not wounded after a battle with Sephiroth. He seems surprised that Warrior would take the time to help him, but our paragon of virtue explains -
Warrior: I trust you as a friend. Just stick close to your path to the crystal.
Firion takes the advice and beats a hasty retreat.
Sephiroth simply looks the other sowrdsman up and down and sums up his arrival with -
Sephiroth: A new-comer?
Sephiroth: You will not obtain a crystal by fighting me.
Warrior: I know.
Sephiroth: In that case, why do you stand against me?
Warrior: You injured my friend.
Sephiroth: And you're saying that you cannot forgive me for it.
Sephiroth: I suppose that I can entertain your request for a short match.
Warrior: Let us begin. We both want to finish this quickly.
Sephiroth: Though, it could be fun.
So they proceed to duke it out and Warrior is victorious. Not as thought Sephiroth seems to have broken a sweat afterwards when seen in their post-combat dialogue.
Sephiroth: Impressive. Your'e the only one other than him* to defeat me.
*(Three choices as to who he is referring to, and the first two don't count)
Warrior: What on earth are you....
Sephiroth: Let me ask you one thing.*
*(and Sephiroth artfully dodges the question of explaining himself)
Sephiroth: Why have you taken up that sword?
Warrior: To obtain the crystals and end this war.
Sephiroth: You are fighting to stop a war?*
*(this is actually a very interesting contemplative line, the delivery startingly similiar to CC!Seph. It quickly vanishes though.)
Sephiroth: What a noble statement.
Sephiroth: So you simply happened to arrive in a place already mired in war?
Warrior: Though we come from far and wide, we have been gathered here to stop it.
Sephiroth: No, you're wrong.
Sephiroth: You are fighting for the pleasure of it, just as I do.
To emphasize his point, he produces the rose he stole from Firion which Warrior instantly recognizes.
Sephiroth: You and I are the same.
Sephiroth: Souls perfectly suited to this closed-off world.
Warrior: Closed-off world?
Sephiroth: Though, one rife with opportunities.
Sephiroth: Either way, I now have to go meet with those bastards*....
*(literally "yatsu" which has several shades of meaning, but given how distasteful Sephiroth's tone is at the thought of dealing with the other villains, I went with the harsher meaning.)
He vanishes at this point. Like most of what the villains say, this does shake Warrior up a bit, but he gets over it.
Also, in Firion's storyline, Cloud is explicitly shown to return his rose to his friend, taking it all full circle.
