Krattorians were a race of blue-skinned, humanoid slave traders. One Krattorian ship, commanded by Kest, landed on Skaro to collect sand. All except Kest were killed by the Daleks, who then captured their slaves and their ship. The Daleks wanted to force the secrets of space travel from them. Although the slaves later escaped in the ship, the Daleks had already learned from it the secrets of space travel.