A respected member of the community, millionaire Dan Kane was good friends with Admiral Edmund Leeds and Professor John Wolf. Kane pretended to have a weak heart while masquerading as boisterous coastal hero the mighty Captain Terror. Becoming famous in his native Georgia, Captain Terror traveled overseas to fight alongside Eugene Judd and communists against fascists in the Spanish Civil War. Kane battled Nazi scientist Black Claw and spy Hans Shiller and was seemingly slain by Delvadian-born hero el Aguila; while Judd attacked the Nationalist citadel seeking revenge on el Aguila, Kane secretly survived, returned to Georgia and retired for years.
In mid 1941, a Nazi merchant raider led by Black Claw, now a captain, targeted American convoys and naval destroyers shipping to Britain. Kane learned of the attacks from Leeds; after talking with Lt. Bill Young, Kane decided to become Captain Terror again to fight the Nazis. Leeds was unable to find the raider, but Kane sped silently alongside the Nazi vessel and revealed their position with the raider's own searchlights. Black Claw fought Captain Terror during the battle between Leeds' cruiser and the raider but Black Claw escaped as his ship sunk. Allowing himself to be captured by Black Claw's men, Captain Terror listened as Black Claw, outfitted with another raider, talked about his invention of "magnetic" mines that could adhere to wood, rubber or steel. After witnessing the mines destroy an American steamer, Captain Terror escaped and planted a bomb near the stored mines, capturing Black Claw before the raider exploded.
Black Claw disappeared beneath the water after struggling with Captain Terror, but the two apparently battled again during an invasion of New York's Holland Tunnel.
Hoping to collection information, Kane invited several US-based heroes including Defender, Rusty, Whizzer, Rockman, Vagabond, Jack Frost and Major John Liberty to his New York residence; they agreed to meet regularly, though further meetings are unrecorded.
Kane learned of Professor Wolf's paint that allowed planes to blend in with the sky; they took the formula to Ft. Gregory's General Garvey and met with the general's daughter, Norma. Wolf's maid Maria, secretly a Fifth Columnist, contacted Shiller, who then met Black Carlo, an American Gypsy working with the Nazis (seemingly unaware of Gypsy persecution in Europe); using a magic crystal ball, Carlo tracked Wolf. An old woman, the rightful leader of the Gypsies, helped Captain Terror capture Carlo; Captain Terror then worked with Army Air Force Lt. Green to capture Shiller.
Gustave Leech, a Nazi scientist specializing in "sudden death," attacked shipments between Arbolivia, South America, to Britain, and Leeds led a convoy to stop him. Using his private plane to arrive there first, Captain Terror fired his pistols at Leech's torpedoes, destroying them before they could hit their marker.
In the capital city, Captain Terror followed a spy he recognized from Spain to Leech's hideout, then captured Delores Madrigo, who revealed she was tricked into helping Leech. After Captain Terror left her, she was captured by Nazis as a traitor and encased in a torpedo shell. Captain Terror released Madrigo and threw the torpedo at Leech's submarine with enough force to explode on impact, defeating the Nazis.
By 1945, Captain Terror had joined other super heroes in Europe, but when the Red Skull used a Cosmic Cube to conquer the world, Captain Terror and others were apparently killed. Time-travelling Avengers, including fellow Spanish Civil War-veteran Wolverine disguised as Captain Terror, joined the Invaders in correcting the timeline and restoring Captain Terror, and others, to life.
Captain Terror subsequently joined in the Battle of Berlin, fighting alongside Captain America.
In modern times, an elderly Kane re-introduced himself to Captain America at a wartime heroes reunion hosted by the Angel.
Trained to peak physical condition with almost superhuman strength, Captain Terror was, in his prime, an expert fighter and master tactician. He could shoot a speeding torpedo with a pistol or throw a knife with precision at over 60 feet, and is an expert pilot and boat captain, skills he put to use with his silent powerboat and Curtiss SC Seahawk, which reaches over 330 mph and is invisible at distances over 200' due to John Wolf's paint. He also has a handheld electro-magnetic searchlight that can stop a speeding torpedo.
Captain Terror maintained a secret underground boathouse beneath his Georgia mansion.