Darkness

Darkness is the parallel force(the other being Light) in the KH universe and is also a form of attack from the Kingdom Hearts games. Darkness is commonly associated with evil due too it's naturally destructive force, but this is not true. Because of it's corrupting power, People can lose they're hearts too it, becoming "Heartless". Those that follow the path of darkness(villains such as Maleficent and Xehanort's Heartless) gain enormous power but usually lose much of their physical selves too it.Mickey's Keyblade represents darkness though he personally follows the path of light.

The Dark element is a form of attack used by Heartless, Nobodies, and some bosses, but not used by Sora, nor his party. Gravity is a form of magic that utilizes darkness. Sora and his party may be protected from Darkness attacks by equipping items such as the Midnight Anklet.

Synthesis
The Dark Shard, Dark Stone, Dark Gem, and Dark Crystal items are full of darkness. They may be obtained by defeating Heartless--usually those that use a lot of Dark attacks.

Dark Shard
Enemies that drop Dark Shards include:
 * Kingdom Hearts 2
 * Shadow