They are a pair of man-eating lions from the Tsavo region, which were responsible for the deaths of a number of construction workers on the Kenya-Uganda railway from March through December 1898. The significance of this pair of lions was their unusual behavior, such as the number of men killed and the manner of the attacks.
They were a duo of two male lions. They were dubbed The Ghost and the Darkness by the people of Tsavo, Kenya, because of their hunting methods. Unlike other lions, they were shown to kill their prey and lick up their victim's skin, and drunk their blood when it reached the surface. And, they would also hunt together, unlike other male lions. They were also believed to have been demons in lion skin. They also kill for pure fun rather than for sustenance purposes. They have killed about 80 people, or more. Because of them, the building of the bridge was halted, and John Henry Patterson was appointed to kill the lions, after he had killed one before. Also joining him was a native African named Samuel, and Charles Remington, a hunter who was appointed by Beaumont when the construction of the bridge was slowing. After a few failed attempts, Remington sets up a trap by using Patterson, and a baboon as bait. This kills one of them. On the following day, the remaining lion carries Remington out of the camp, and kills him. Seeking vengeance, Patterson burns the grass surrounding the grass to lure the lion out. This results is them ending up in the unfinished bridge, and Patterson kills the surviving lion. The bridge construction is then completed. Samuel, who had been narrating the movie, says that the carnivorous man-eaters can be found at the Field Museum in Chicago, Illinois.