Celestial Pain Star, Mandrake Fyodor is an extremely sadistic Specter, who has his own torture chamber in a ruined building near the entrance of Hades. From the Water Margin story, his star originates from the main character Wu Song.
He has his own torture chamber in the depths of Yomotsu Hirasaka, the Hill to the Land of Spirits.
He held Tenma captive until the Pegasus Saint was rescued by Yato and Yuzuriha, and then was slain by his former prisoner.
Later he was resurrected by Hades.