These aliens are a near-human people with extreme intelligence. They enslaved the Yaka from nearby planets, turning them into cyborgs.
Their home planet, Arkania, is not truly their homeworld at all, but was originally a repository for Sith knowledge. One famous Arkanian was the ancient Jedi Master Arca Jeth. Arkanians have three fingers and a thumb on each hand, and can see well into the infrared range of the electromagnetic spectrum.