The MCU, or Marvel Cinematic Universe, has brought dozens of Marvel Comics' best characters to life on the big screen and the MCU's cast of characters is more colorful and diverse than ever before. These comic book characters vary not just in their costumes and their superpowers/weapons, but also their personalities.

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These MCU characters range from bitter loners to inspiring leaders and everything in between; some characters are merciful to their enemies while others are not. All MCU characters fight to win, but some of them are truly brutal and hold nothing back while others fight fair and let their opponent live to see another day.

10 MERCIFUL MCU CHARACTER: Captain America Fights To Win, Not To Kill

Captain America running with his shield

Steve Rogers, the skinny kid from Brooklyn, always had what it took to become a great hero and the super soldier serum made his dreams a reality. He fought the cruel Red Skull and HYDRA during World War II, then awoke in the 21st century to battle the forces of evil once again.

Despite his many losses and setbacks, Captain America maintained his heroic spirit and never stooped to cruelty or revenge in his career. He fights not to slaughter his enemies or prove himself, but to defend the innocent. His noble spirit is just as unbreakable as his Vibranium shield.

9 MERCILESS MCU CHARACTER: Thanos Is A Living Apocalypse

thanos endgame mcu

In Thanos' own eyes, he is being merciful by sparing half the universe while killing the other half to conserve resources. He also allowed Doctor Strange to live after acquiring the Time Stone. Aside from that, Thanos is a merciless and unstoppable villain who sees no need for compassion or pity to anyone.

Thanos is determined to succeed — he burns with self-righteousness. He will gladly send any minion to their death if it means victory. He slew Loki without mercy in the opening scene of 2018's The Avengers: Infinity War. He also flung his foster daughter Gamora to her death to acquire the Soul Stone.

8 MERCIFUL MCU CHARACTER: Ant-Man Fights For Survival

Scott looks disgruntled as he's stuck in a hole

Scott Lang is a reformed burglar who got his hands on Hank Pym's amazing suit, which allows him to change his size at will. Now Scott Lang is the amazing Ant-Man; his first major mission was to help Hank prevent his own technology from being abused by Darren Cross.

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Ant-Man is a creative and quick-thinking hero who will do anything to get the job done, but he's not brutal about it and he doesn't take lives if he can help it. He would much rather sneak in, get the goods, and escape before anyone can catch him.

7 MERCILESS MCU CHARACTER: Rocket Raccoon Is Downright Ruthless

Rocket pointing

Rocket Raccoon was a relatively obscure Marvel character until he starred in Guardians of the Galaxy as a wisecracking and memorable antihero. He is a small but tough animal who can steal anything and fly a wide variety of ships and he tends to see things in terms of profits and opportunities.

Rogues like Rocket Raccoon tend to be merciless and practical and even as a team-oriented Guardian, Rocket is rather merciless and vicious, even toward his allies at times. He'll say, do, steal, or shoot anything if it means getting what he wants, often putting him at odds with Star-Lord.

6 MERCIFUL MCU CHARACTER: Spider-Man Refuses To Shed Blood

Spider-man lookin' cool

Peter Parker is a good-hearted young man who has sworn to keep the streets of New York City safe from crime and he will do it his own way. Spider-Man is a tough and smart fighter, but Peter won't ever take a life, as Spider-Man: No Way Home showed. He saw Lizard, Electro, and Sandman as victims who needed help, not monsters to be killed.

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Spider-Man's sense of mercy and compassion has turned against him more than once, but fans love him because he is a kind and noble fighter, not because he's the strongest. It helps that his best technique, creating webs, is ideal for rescue and capture operations rather than for killing.

5 MERCILESS MCU CHARACTER: Malekith Held Nothing Back

Malekith the Dark Elf from Thor: The Dark World

Malekith was the leader of the ancient and mysterious race of dark elves and in Thor: the Dark World, Malekith and his minion arrived to ruin everyone's day. Malekith had a serious vendetta against the Asgardians; he showed no mercy when he stormed Asgard with his small but powerful fleet.

Malekith's ship plowed right into the Asgardian palace and Thor's mother, Frigga, was killed in the fighting. Malekith even turned one of his own followers into a brutal monster for the sake of the mission.

4 MERCIFUL MCU CHARACTER: Star-Lord Would Rather Prank Everyone Than Kill Them

Star-Lord Milano Guardians of the Galaxy

Peter Quill/Star-Lord is, in many ways, the Ant-Man of outer space. He is a lovable rogue who is more interested in zany heists than fighting people to the death. According to both Star-Lord and Ant-Man, it's possible to finish a job without shedding a drop of blood.

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Star-Lord is no pacifist and there have been times when he wanted someone dead, such as Thanos after the he admitted to sacrificing Gamora. As a whole, though, Star-Lord is more interested in stealing goodies and pranking his enemies than killing them.

3 MERCILESS MCU CHARACTER: Gamora Was Trained To Kill

Gamora holds up her weapon

Gamora is Thanos' foster daughter; she was trained since her childhood to become a deadly assassin who favors blades and small arms. Gamora is a practical and self-sufficient humanoid alien who doesn't ask for much or give much in return.

Gamora softened a bit when she became involved with Star-Lord, but she never forgot her training and she shows mercy to few MCU characters. Almost everyone is fair game for her blades if it means accomplishing the mission. She will even take her own life if it means denying the enemy what they want.

2 MERCIFUL MCU CHARACTER: Shang-Chi Fights For What Is Right

Shang-Chi wielding the ten rings in his debut movie

Shang-Chi is a martial artist hero who was trained since his childhood for assassination, just like Gamora. His ancient father, Xu Wenwu, wanted Shang-Chi to be his ultimate tool, but Shang-Chi grew disillusioned with this lifestyle and ran away, leaving behind his single father and his younger sister, Xu Xialing.

Shang-Chi will fight to his last breath to protect the innocent and defend justice, but he sees no need to shed blood. He didn't even kill the assassins who tracked him down in San Francisco and it was with great reluctance that he finished off his father and claimed the Ten Rings for himself. Despite his training, Shang-Chi isn't a killer at heart.

1 MERCILESS MCU CHARACTER: Black Widow Puts The Mission First

Natasha (Scarlett Johansson) in Black Widow

Black Widow is yet another MCU character who was trained since childhood to be the ultimate assassin and weapon. While Black Widow is a fine Avenger and defender of Earth, she is rather merciless compared to the likes of Spider-Man and Ant-Man. She has her merciful side, but it doesn't appear often.

When there's a job that needs doing, Black Widow will do anything and everything to accomplish it; she never hesitates to strike down anyone who gets too close to her. She is never sentimental in battle and will coldly take down anyone in her way. The main exception was when she allowed Steve Rogers and Bucky Barnes to escape at the last second during the airport battle.

NEXT: Eternals: The 10 Most Mature Characters, Ranked