Langdon Caul A.K.A. Abraham Sapien is a paranormal investigator. He is often an ally of Anung Un Rama.

Abe is a humanoid amphibious creature. He has a pair of gills on his neck, allowing him to breathe underwater, but also has a set of normal human lungs allowing him to stay above and out of water for long periods. However, he does need to regularly "get wet" to keep him from becoming too weak. Abe possesses webbed hands and feet, and has large, bright eyes that help to see in murky, thick water. He has distinctive black/blue stripes vertically overlapping his forehead in a shape reminiscent of a "V", and easily ranks as an Olympic-level swimmer, if not actually surpassing that measure, thanks to his highly athletic physique.