The Wizard of Reay, also known as Donald MacKay is a dark sorcerer from Scottish folklore and he is sometimes considered more evil than Satan himself.
The Wizard of Reay studied dark sorcery in Italy, under the skillful tutelage of the Devil himself. When his exams were over and it was time to go, the Wizard rose with the other students, and Satan tried to grab the Wizard's soul for his own. But the Wizard was far too quick for him, he saw Satan's plan and ran for it, yelling "The Devil take the hindmost!" and Satan only grabbed the Wizard's shadow. From that day on, the Wizard was without a shadow, and Satan was eager to grab the rest of him.
Meanwhile, the Wizard of Reay made up a name for himself by kidnapping, robbing, torturing and then drowning numerous people in his region of Scotland. He passed himself off as a respectable figure and thus he got away with it - but he was deeply barbaric, sadistic and cruel under his guise.
The Devil tried numerous times to grab the Wizard's soul:
First conflict with Satan
Once, the Wizard of Reay was on a midnight hike in the cave with his dog familiar, when suddenly the hound ran off onto another part of the cave. Suddenly, there was an explosion and a singeing smell, and the dog ran back in squealing without any hair left on it. The cunning Wizard knew that Satan was waiting nearby to claim his soul, so the Wizard only escaped because dawn broke and the Devil fled the light. Another version says the Devil was accompanied by two witches, apparently the Smoo Cave has three holes in its roof, said to be made by the Devil and his hags when they flew back to Hell.
Second conflict with Satan
Another time, the Wizard of Reay was out walking again in Smoo Cave when suddenly he came upon a little wooden box on a rock. Curious, the Wizard opened it, and suddenly a little man popped out. Soon the small man began to grow, larger and larger, until the terrifying form of Satan stood before him. The arrogant Devil demanded the Wizard's opinion of his trick. The Wizard said it was all good if Satan could come out of the box, but what about going back in? The Devil was too vain to ignore this, and showed off his power by shrinking once more into a tiny figurine. The Wizard of Reay cunningly picked up Satan and tossed him back into his box, locking it tight, trapping the foolish Devil and saving his soul yet again.
The Wizard of Reay was a very cunning man and unlike other sorcerers, he used a combination of dark magic and wits to get out of peril. He is very similar to Crowley, and Crowley may have been based on the Wizard of Reay, in part, given both are Scottish.
The Wizard could pass himself off as a dignified nobleman yet underneath this was a bloodlust and a cruel dark soul, which the Devil obviously saw as worthy of belonging to him.