The story "Kings of the Night", in which Kull is summoned forward in time to help battle a Roman army, references a decline of the Picts after the age of Kull, specifically noting the Picts lost the skills of metalworking.
In the fictional tale "Kings of the Night," Kull is called upon to aid in a conflict against a Roman army. The narrative suggests that the Picts experienced a decline following Kull's time, particularly losing their proficiency in metalworking.