One of Marvel's oldest and most prominent heroes, Captain America has had his fair share of epic and intense battles in his storied career. From his time working alongside the Howling Commandos in the Second World War to the grandiose contemporary clashes alongside the Avengers and other Marvel heroes, Steve Rogers has fought all sorts of threats.
True to his nature as a soldier, this Avenger is not one to shy away from ending his opponent's life if he is pushed to make such a fatal decision. He may not be as bloodthirsty as the likes of the Punisher or Deadpool, but Cap will do what he deems necessary in that moment.
Most of the people he has encountered in battle have been normal (albeit well-trained) humans and low-level superhumans, but the hero has occasionally gone up against foes far beyond his peak human capabilities.
Under ordinary circumstances, these powerhouses would wipe the floor with the super-soldier. But due to a combination of factors (both simple and convoluted in nature), Rogers has wounded, defeated and killed these beings in displays of power and skill that are both terrifying and awe-inspiring.
10. The Colonel - The Ultimates Vol. 2 #12
The Ultimates line of comics serve as an interesting time-capsule of sorts, capturing Marvel's rough yet inspired attempt to place its characters in the modern-day in the early 2000s. While this did not always resonate with fans, it served as a fascinating counterpart to the then-main, Earth-616 timeline.
During the first run of the second volume of the Ultimates, the eponymous team (this universe's Avengers) was tasked by the U.S. government to conduct pre-emptive strikes on Global South nations to dismantle their weapons program.
Naturally, this triggered the affected nations to develop their own superhuman team known as the Liberators and chief among them was the Colonel, Azerbaijan's answer to Captain America. Once a scrawny teenager, Abdul Al-Rahmani became the second person to be enhanced by the Super Soldier Serum after Steve Rogers himself.
The Liberators went up against their American counterparts and the two super-soldiers engaged in battle, with Al Rahman eventually losing his hands due to the Hulk's intervention. This gave Cap the chance to overwhelm his opponent and stab him with his own weapon, killing the Colonel instantly.