Icicle: 1942, Four Favorites #7 (Ace). The Le Mair brothers in France perfected a quick freezing refrigerating process. When the Nazis invaded, one brother escaped to America and the other, Rufino, joined the Nazis and became the quick freezing Axis agent known as the Icicle. The Icicle came to America to stop his brother from building a plant for freezing foods to send over seas. The Icicle wears a rumpled suit and his white hair and face seem to have ice hanging off. He kills with a touch but that's because in his bulky suit, he carries the quick-freezing gas that he lets out with a tube by his hand. However, he is apparently killed when the tube is crushed while fighting the Unknown Soldier and the gas feeds back onto the Icicle.
Immortal Emperor: (Better). Tall and lanky with a cylinder head and a face like a wall outlet, he teams up with Lilith and Dr. Voodoo in efforts to defeat Wonderman II and conquer the solar system.
Indira: 1940, Reg'lar Fellers #2 (Eastern Color Printing). The beautiful Indira is the Queen of Dacoits in modern day India. Her goals for power have two obstacles: Kalla Khan who rules a thuggee cult and the American writer Chickering Mann.
The Invincibles: 1941,Yankee Comics: 3 (Chesler) The Invincibles are foreign soccer team is secretly made up of spies to spread Nazi propaganda. When their underhanded and rough playing decimates the ranks of the American team, the kid gang Young Americans get involved. The Young Americans is a bit different from most kid gangs in that it actually has at least 2 girls and one African American as part of the group, all playing active and equal parts in the story.
The Invisible Menace: 1941, Dynamic Comics #2 (Chesler). A crook and his two henchmen break in on a scientist who had recently revealed that he discovered an invisibility formula. The scientist is killed and there's only enough serum for one person. The boss then kills his two men and drinks the formula, becoming "The Invisible Menace". He goes on a stealing spree, but thinking mostly small time, stealing wallets, necklaces, assault, etc. Detective Dick Starr brings K-9 on the case who sniffs the hat that the Invisible Menace left behind. With his superior senses, the dog is able to find the man, even when invisible and when he's about to kill, K-9 attacks, apparently killing him by biting him in the throat. When dead, the formula wears off and the man becomes visible once more.
Iron Jaw I: 1941, Silver Streak Comics #9/10 (Lev Gleason). This Iron Jaw is a robot that is working for and directed by the leader of the "Axes" (sic), a foreign dictator. He's heavy and strong. Not too agile but good enough to go a round or two with the hero Silver Streak. Until he is thrown off a building and smashes to bits. Note: In issue 9, he is referenced as being behind various attacks but is not seen. It's issue 10 that reveals him and continues the story. Also, in issue 9, it is suggested he is the ringleader, but as he's revealed to be a robot, it is supposed that there is even a higher leader that radio controlled him. This is not followed up on.
Iron Jaw (II): Boy Comics (Lev Gleason). An incident during WWI left a German soldier by the name of Von Schmidt horribly disfigured and doctors were forced to replace his jaw with one of metal. He's a vicious soldier who has been reported dead many times. He killed Chuck Chandler's father for daring to speak out against the Nazis. A German sub sank the transport bringing Chuck and his mother over from France, and gunned them down in the ocean. Surviving, Chuck became the Crimebuster, Iron Jaw's most implacable foe. Iron Jaw could take a large amount of punishment, such as a chair breaking across his head without flinching and was thought to be dead on at least one occasion.
Princess Istrid: 1939, Amazing Man Comics #8 (Centuar). Haughty Princess Istrid is the step-daughter of Kustan, the ruler of the subterranean kingdom of Aquatania. She resents the popularity of the outsiders Chuck Hardy and his blonde girlfriend Jerry and would like to see them dead. She meets her own untimely end in a foreign land a couple of issues later when men that were bribed to carry her back home just kill her on the way as they already have the gold and no one would know.