Unfortunately no. They weren't really a problem until a few years ago. Ansem the Wise's disciple Xeahanort ignored his master's warning and did extensive reasearch on the Heartless. He's the reason they're so active.
The sourece is the Realm of Darkness.
edited 17th May '12 7:52:46 AM by Jamdat369
"All worlds begin in darkness and all so end. The heart is no different."-AnsemTo me? Well....I was a secretary at a lab facility, and I was under Chief Kurama. I'm not too sure what they did in that facility, but all I was concerned about......was pleasing Chief Kurama.......(blushes)...a-as his secretary of course! Nothing more! Ha-ha.........
(a random green haired kid walks in humming a tune)
It's a beautiful day in the neighbourhood, a beautiful day in the neighbourhood, would you be mine? Could you be mine?
edited 17th May '12 8:11:56 AM by LatverianBadger
"Shake the dust." - Anis Mojgani

Probably.
-to Leon- Has he pulled his head out of his ass yet?
MY SOUL IS DARK BUT MY HAIR IS COLORFUL — Brahian Pokémon Alchemist