There is something to be said about beauty. Fades fast, drives men and women to madness simply to attain, to restore, to improve it. Fools seek it, paying the price for beauty until they are spent and drained, and the beauty has faded.
The beautiful things in life, after all, do not come cheap or easy, but are gone before you know it.
Onigumo had always been fascinated by the beautiful things. He would catch fireflies, capture them and keep them until they were burnt out and dead.
And he would catch more. There was always more.
Greed is so simple, so amazingly pure in the young.
When he grew up, Onigumo found out there were much better, more beautiful things than fireflies. Like the soft curves of a woman, like the sharp mirror-steel of a blade, like the glittering wonder of precious stones.
He paid for these beautiful things in blood and fire and the screams of the dying.
And he enjoyed it.
Then, once upon a time, he heard about the most beautiful thing of all.
The Shikon no Tama.
A pink, innocuous jewel said to have the souls of demons and a miko and the power to grant a wish, and with beauty that rivaled the stars.
Oh, he would have it. He would have this beauty for his own, and treasure it- not for a wish or for power, but simply because it was beautiful.
There was no price too great for beauty.
Even... even his body, his soul.
Onigumo traded his body to the fire, was consumed in the pursuit of the beauty of the Shikon no Tama.
Onigumo traded his soul to demons, was devoured so that he might gain this beauty, be able to posses it for himself.
Pain was no obstacle. Death was no obstacle.
Only beauty, the beauty of the Shikon no Tama mattered anymore.
It was desire, beyond want or obsession.
Desire, the power that fuels all action, all thoughts and all ideas.
Naraku became that desire, from Onigumo's wretched soul and that desire for the beautiful.
The Curse of the Shikon no Tama affects all, after all.