History
Marshall Kronin was a member of the Nazis during World War II. In the fall of 1943, following repeated failures to destroy the Sub-Mariner, Kronin suggested they use an alternate means of striking at the hero: Kidnapping his sometime ally, policewoman Betty Dean. They succeeded in kidnapping her from New York City and brought her to Berlin, Germany.
As expected, when news reached the Sub-Mariner, Namor went to Berlin to confront Kronin. However, he surprised them by stating that he didn't care about Dean and that he instead came to pledge his allegiance to the Nazi cause. Kronin was completely sold on this declaration and was told by Namor of a convoy passing near Murmansk, Russia and how to attack it. This however, was all a ruse and Namor intended to lead the Nazis into a trap. However, plans were complicated when the Nazi propaganda machine was able to get the news about Namor's "betrayal" out to the world before he could tell Allied Forces his plans. Despite this, he still managed to lead Nazi ships to their destruction, although he was knocked out and taken prisoner by the Nazis -- who then realized his duplicity.
Namor was taken back to Berlin and locked in a cell, where Kronin confronted him to personally execute the Altantean. However, Kronin got to close to Namor's cell, and the Sub-Mariner broke out and used Kronin as a human shield to get to Betty's cell and free her as well. With Betty free, Namor easily escaped Kronin and his men and fled from Germany in a stolen Nazi fighter plane.[1]
Kronin's subsequent fate is unknown.