Carl is the uncle of Seth and Kendra Sorenson and their father's brother. He also has a sister named Aunt Sophie, the Aunt of Kendra and Seth. He, like his siblings hardly ever visit his parents now that they own the Fablehaven Preserve. He does not know about the existence of magical creatures, nor does his sister. His brother, Kendra and Seth's father, though, discovers magical creatures exist in the fifth book after being held capture by some, along with his wife Kate.