Hamuka was a saboteur during World War 2 who ran afoul of the Fighting Yank and was killed by his own bomb, an all-too-common fate for comic book wartime spies.
References: [Fighting Yank #1] [1942] [Japanese spy and saboteur, foiled by the Fighting Yank; blown up by his own bomb; “You dare to cross Hamuka? I have ways to make you talk!”; ]
Metahuman Database 