Alzur was a famous mage and the inventor of many spells, including Alzur's Double Cross, Alzur's Shield and Alzur's Thunder. He is also known for having created many horrible monsters, some of which still roam the world. He is said to have had a voice and diction which were positively mellifluous.
During his visit in the Outskirts of Vizima, the witch Abigail tells Geralt about the time Alzur the mage met a beast immune to magic. The beast asked the mage a question, and by answering correctly Alzur was able to defeat it. Thenceforth, the beast was known as "Alzur's demon".