Heroes in the world of anime are often role models for viewers - most often in shonen anime where the protagonist embodies many noble traits from humility to true grit and faith in one's friends. These anime heroes must face all sorts of powerful villains to save the day, but they don't always show mercy in the process.
Most anime villains are completely merciless and brutal, as expected, and sometimes, anime heroes return the favor. Those anime heroes never hesitate to deal the final blow and exploit every weakness they can find in their enemy, and the villain might be taken by total surprise. Still, there are plenty of anime heroes who show compassion or mercy.
10 MERCIFUL ANIME HERO: Tanjiro Kamado Comforts Demons As They Perish (Demon Slayer)
Tanjiro Kamado is the hero of Demon Slayer, and there is only one demon who has earned his absolute hatred: Muzan Kibutsuji, the one who slew the Kamados and turned Nezuko into a demon herself. However, most other demons are actually victims deep down, and Tanjiro knows it.
Tanjiro won't let demons go once he finds them, but he will treat them with basic respect and dignity as they die. He might even offer comforting parting words to them, as he did with Kyogai, who wanted just one person to appreciate his failed manuscript. Tanjiro will even shed tears for a dying demon.
9 MERCILESS ANIME HERO: Kakashi Hatake Will Use Any Jutsu To Win (Naruto)
Kakashi Hatake is a famed anime mentor and hero, and while he has a good heart like Naruto Uzumaki, he's not as idealistic, and he's not about to deliver a talk jutsu to convert a fallen enemy into a friend. Instead, Kakashi will fulfill his mission to the letter, no matter how much blood must be shed.
Kakashi appreciates Naruto's merciful ways, but in general, Kakashi refuses to emulate them. He'll gladly use any advanced jutsu, from Kamui to copied techniques, to crush his enemies and aim to take their lives. He once tried to vaporize Deidara with the Kamui, but Deidara escaped by losing only an arm.
8 MERCIFUL ANIME HERO: Chad Is Polite To His Enemies (Bleach)
Ichigo Kurosaki's good friend Chad is a strong and tough fellow, and in his youth, Chad vented his frustration by beating up local kids while living in Mexico. All that changed when Chad learned the true meaning of strength, turning him into a semi-pacifist.
During the main events of Bleach, Chad can use spiritual powers in his arms, and while he's brave and powerful, he won't revert to his bullying ways. He defeated an Arrancar named Gantenbainne, then spared his life and even thanked him for being such a great opponent. Gantenbainne was impressed.
7 MERCILESS ANIME HERO: Jotaro Kujo Has No Time For Games (JoJo's Bizarre Adventure)
Jotaro Kujo, the hero of the Stardust Crusaders story arc, is one of shonen's most notorious antiheroes due to his cool, aloof and even thuggish personality. He aims to save his mother's life and crush DIO like a true hero, but he won't act warm and cuddly along the way.
Jotaro is grouchy with his allies, and he's downright monstrous to his enemies. In a Stand battle, Jotaro can seek out and exploit the enemy's weakness with remarkable ease, and he won't hesitate to deliver a bone-crushing beatdown with Star Platinum. Never does he hold back.
6 MERCIFUL ANIME HERO: Edward Elric Has Vowed To Never Kill (Fullmetal Alchemist: Brotherhood)
Edward and his brother Alphonse are talented alchemists, but they refuse to misuse their abilities ever again. After their failed attempt at human transmutation, the brothers vowed to recover their bodies and help other people in need.
Ed faces many foes, but he won't take their lives. He wouldn't even kill Scar the Ishvalan monk, especially since Scar had already suffered so much. Ed will happily incapacitate or capture someone, but he won't shed blood. There was a time Solf J. Kimblee exploited this attitude, and Ed nearly died because of it.
5 MERCILESS ANIME HERO: Laxus Dreyar Goes All Out (Fairy Tail)
At first, the lightning dragon slayer Laxus Dreyar was actually an antagonist, but that didn't last. Overall, Laxus is a hero, and he is roughly on Natsu's and Erza's level. He fought for the Fairy Tail Guild in the Grand Magic Games arc, and again in the Tartaros story arc.
Laxus has a brutal and merciless attitude, and enjoys going all out to crush his enemies and prove himself. Even as a hero, he's thuggish and revels in his strength, and won't waste an opportunity to pound Fairy Tail's enemies into dust.
4 MERCIFUL ANIME HERO: Rimuru Tempest Forgives & Recruits His Former Enemies (That Time I Got Reincarnated As A Slime)
Despite his overwhelming power and many abilities, Rimuru Tempest the slime hero rarely takes lives, and when he does, it's because things have already gone horribly wrong. His major merciless act was to kill thousands of Falmuth troops to fuel his transformation into a True Demon Lord.
That was an exception. Otherwise, Rimuru is highly merciful and tends to defeat his foes bloodlessly, then recruit them as allies - even an entire army of ravenous orcs. This is how he built up such a huge, diverse kingdom of loyal subjects. Mercy is the new rule of the land.
3 MERCILESS ANIME HERO: Mikasa Ackerman Won't Hesitate To Fight (Attack On Titan)
Mikasa Ackerman has a serious soft spot for her friend Eren Yeager, and she is remarkably cool-headed and aloof if Eren is safe and secure. But when Eren is threatened, Mikasa will go into a frenzy, and won't stop until her enemies are slaughtered and Eren is rescued.
Mikasa's allies and superiors know that Mikasa needs to be restrained sometimes, and they have held her back when Eren was in trouble. If something threatens her or Eren's life, Mikasa will butcher it in seconds, showing skills nearly on par with Levi's as a fellow Ackerman.
2 MERCIFUL ANIME HERO: Avatar Aang Seeks Peace, Not War (Avatar: The Last Airbender)
Avatar Aang may be a silly kid at times, but he is also a monk and an Air Nomad. He has sworn to never take lives, and he is even a vegetarian. Aang also has a duty to the world as the Avatar, meaning he must defeat the Fire Nation and dispatch Fire Lord Ozai personally.
Aang found a way to get all this done without taking any lives, and at the last minute, he obtained energybending, using it to rob Ozai of his firebending for all time. Even with the world at stake, Aang showed mercy, and though Ozai mocked him for it, Aang was most certainly the winner.
1 MERCILESS ANIME HERO: Captain Byakuya Kuchiki Knows His Duty (Bleach)
Chad may be a merciful hero in Bleach, but Captain Byakuya Kuchiki certainly isn't. He was a villain at first, a major antagonist of the Soul Society arc, and he was a merciless and cold warrior bound by the law. Even when he became a hero, he was still merciless and disciplined as a fighter.
Byakuya faced the 7th Espada, Zommari Rureaux, and did whatever it took to win, even when Zommari made an emotional appeal about the plight of Hollows. Byakuya also showed no mercy to the Fullbring warrior Tsukishima. He has a duty, after all, and that duty doesn't involve coddling the enemies of the law.