Captain America is a fictional superhero created by writer Joe Simon and artist Jack Kirby for Marvel Comics. He first appeared in 1941 and is known for his iconic shield and patriotic costume. As the alter ego of Steve Rogers, he embodies the ideals of bravery, justice, and sacrifice, often leading the Avengers in their battles against evil. Originally a frail young man, Steve Rogers is transformed into the super-soldier Captain America through an experimental serum during World War II. He fights against the Axis powers and later becomes a symbol of hope and resilience, inspiring generations of fans around the world.