Some thoughts on the shape of violence in anime, kind of an outline:
Anime directed at children and young adults often involve a good deal of explicit violence, and even killing. But it is notable that the focal character(s), the one that the watchers are supposed to identify with, rarely kills. Allied characters may kill, but the pov character doesn't.
Consider Yu Yu Hakusho. It's a fight anime, the characters do nothing but fight, all the livelong day, against people who often want to kill them. But Yuusuke and Kuwabara never kill their opponents. They beat the living snot out of each other, but it's Honorable Fights. When there is a truly loathsome character who begs to be killed, he often is. But it's Kurama or Hiei who does it.
Consider Romeo x Juliet. Juliet goes out and rescues citizens from armed guards; she fights capably; but she does not kill. In fact, a character point is made of her distaste for killing. When the plot demands that someone die for the viewers' emotional satisfaction, she is provided with an ally who has no qualms about killing, and is shown to do so against her wishes.
Consider Rurouni Kenshin. Again, a character point is made of Kenshin's desire to never have to kill again. He spends the whole story fighting in deadly earnest with swords, but when an enemy character dies it's by their own hand or an ally's hand or by
happenstance.
Consider Digimon. Most enemy characters are cleansed or incarcerated, rather than killed. When the Final Boss characters are destroyed, they are presented, not as individuals, but as elemental forces to be dispersed. And even Final Boss characters are only so dispersed if they are digimon; human characters are never killed.
There are exceptions, to be sure. The Gundam series is a prime one. Even there, though, the focal characters are rarely
shown killing, and, when they are, are often presented to us as temporarily insane.
Shows directed at adults have more varied approaches to violence and death, but the moral of shows directed at young viewers is remarkably clear and unified: manly, bloody brawls and finely finessed duels for justice are well and good, but killing makes you morally ambiguous and probably outcast.