Who is Ian Forest from Shadows in the Darkness and what is their importance?

Ian is part owner of Underhill and an Elder of the Celtic Otherworld. His partner is an older man with silver hair. When Gwen begins investigating Meredith's disappearance, she purposely applies for a job as a dancer at Underhill, where Ian immediately realizes she is "one of them". His realization prompts him to do a background check, during which, he learns that she is not a dancer..... she is a private investigator.