Cmdr. Don Winslow
Mercedes Colby
Spencer Merlin
Lt. Red Pennington
Misty Gaye
Mike Splendor
John Blake
Paul Barsac
Henchman Corley
Henchman Spike
Seaman Chapman
Henchman Prindle
The Scorpion
Gang Radioman Barker
Lt. Cdr. Grady
Admiral Warburton [Ch. 1]
The CINCUS [Ch. 1]
Capt. Holding [Ch. 1]
Enemy Sub Capt. Tranker [Ch. 1]
Capt. Fairfield, of the "Batavia" [Chs. 1-2]
Tangita Jim [Chs. 2, 10]
Capt. Sanders, of the "Tarleton" [Chs. 3-4]
Saboteur Kramer [Chs. 3-4]
Lead Henchman at Mill [Ch. 5]
Native Henchman at Mill [Ch. 5]
Witch Doctor Koloka [Chs. 6-7]
Sub Capt. Jackson [Chs. 7, 9]
Sam Munn, henchman [Ch. 8]
Henchman Butch [Ch. 8]
Gang Chemist Taylor [Chs. 8-9]
Taylor's Lab Assistant [Ch. 8]
