Eyewitnesses to gruesome monster attacks always have a hard time describing the creature in question. The beasts move quickly and often attack at night, while the witnesses are terrified and primarily concerned with fleeing for their lives. As a result, witchers quite often have no inkling what creature they face until they find tracks or otherwise establish something for themselves. Such was the case with the Beast tormenting Beauclair. Geralt knew it was deadly, elusive and fiendishly clever. Everything else he heard was clearly the product of imaginations fed by fear of a dangerous predator.
When Geralt identified the Beast, he discovered it was a higher vampire, meaning one of the most difficult foes a witcher can come to face.
Higher vampires are superhumanly strong and fast. They can turn completely invisible, and each comes with its own personalized set of talents and abilities perfected through centuries of existence.
When Geralt realized he was dealing with such a creature, he swore foully and realized the rumors about the Beast had not been exaggerated in the slightest.
The case of the Beast of Beauclair could bey based on the historical case of the Beast of Gévaudan, an allegedly man-eating creature who wounded and killed hundreds of people in Southern-Central France between 1764 and 1767.