Cpt. Steven "Steve" Rogers a.k.a. Captain America, the First Avenger, was rejected by the U.S. Army during World War II due to numerous health problems. He ultimately volunteered for Project Rebirth where he received the Super-Soldier Serum developed by Dr. Abraham Erskine. The serum greatly enhanced his frail body to the peak of human physicality. As the Sentinel of Liberty, alongside his best friend Bucky Barnes and the Invaders, Rogers and others helped the allies win the war, but not before he was lost at sea and frozen in ice in a form of suspended animation for decades. He was thawed out in the modern age to continue the battle alongside his new allies the Avengers. Cap is loyal to no politician or government and instead upholds the "timeless principles of freedom, equality and justice of the American Dream".