Giant Sized Invaders #1 (1975)
"The Coming of the Invaders!" Written by Roy Thomas. Art by Frank Robbins and Vince Colletta.
Long before the Avengers, there were the Invaders. Captain America, the world's first super soldier, Prince Namor, the world's first mutant, and the Human Torch, the world's first android, and their sidekicks Bucky and Toro to form the Invaders.
The greatest heroes of the Golden Age unite to win World War II and take down the Axis Powers once and for all. Their first mission: the Invaders race against the clock to save the Prime Minister of the United Kingdom, Winston Churchill, from an assassination plot.
NOTE: 1st appearance of Master Man.