Kraahkan

The Kraahkan was the Kanohi Mask of Shadows, a mask of incredible power. it allowed the user to control the shadows and feed fear and/or anger into those affected by its power. It also gave the user the ability to see the darkness in the hearts and souls of other beings. When Makuta shapeshifted, the Kraahkan also changed shape - it has been transformed to look like a Hau at least twice.

When Makuta and Takanuva merged to form Takutanuva, the Kraahkan and Avohkii also merged, forming a mask with the powers of both Light and Shadow, or unofficially known as the Mask of Light and Darkness by Greg Farshtey. However, the two beings, and their masks, soon split apart again.

After the Piraka reached Mata Nui, Reidak threw the Kraahkan into the water surrounding Metru Nui because when he picked it up, it kept blasting him with Shadow energy.

Sometime after this, a Makuta named Icarax was sighted diving into the Silver Sea, and emerging with the Kanohi Kraahkan.

Trivia
In one of the 2004 Bionicle playsets, a golden Kraahkan was included.
 * The Kraahkan was made by the residents of Artakha.
 * Greg Farshtey has hinted that another member of the BoM wore this mask before the Makuta of Metru Nui.
 * There is only one Kraahkan.
 * A new Kraahkan will be released in 2008, included in Icarax set. It is the same shape as it was in 2003
 * The Dark Hunter named Darkness appears to wear a Kraahkan shaped mask.