I once made a post on CxA mocking rabid Clotis who demonize Aerith, and I make her out to be yes, the grand architect of everything wrong in the world.
Just read this on TV Tropes, not my theory but it makes sense. These are the lyrics to the Final Boss music Dissidia, named "Chaos".
The Messenger is
Standing at the gate.
Ready to let go,
Ready for the crush.
Too late for whispers,
Too late for the blush.
The past is mercy,
When the future's glow.
Kneeling journey,
Dressed in a cloak of shadows.
The hunting’s grim for the innocent eyes.
Communion’s pray is a cup of sorrows.
But faith is colors,
For the humbling cries.
The pilgrims are gathering and the marching band,
The marching band’s howling.
Compassion is the flag a righteous man,
A righteous man will hold.
The pilgrims are gathering and the marching band,
The marching band’s howling.
Compassion is the flag a righteous man,
A righteous man will hold.
The spirit is over town,
Waiting for me to hit the floor.
Blooming white sky for the voice of one calling tonight
Tonight fate is the red crown,
The red crown around your door.
Time’s scattering the seeds of the morning daylight.
Apparently the lyrics are meant to not have any specific meaning, but they kinda fit Chaos during the battle. By the time the heroes get to him, Chaos has regained his lost memories of the time he was a good god who ruled the world with Cosmos, until Garland got to him and convinced him to begin the war. So as he's fighting the heroes, Chaos is taking out all the turbulent emotions he's experiencing on them - grief, rage, hatred, sorrow, etc. He's now prepared to destroy all existence because a world without Cosmos is one without meaning to him, he has nothing left worth living for. But in the same stroke, perhaps he
wants the heroes to kill him, so that the worlds are restored and he can die and be with Cosmos again and not have to live with the pain of knowing he killed his former co-ruler and one true equal.
So yeah, according to the theory, the song "Chaos" is about Chaos - Chaos wants the heroes to destroy him to free him from his grief and despair, and because he knows the worlds can't be set right again unless they do.