In this era, people put their lives on their beliefs, their stance and their battles. When Luffy goes to the battlefield, Luffy destroys the beliefs of others "
Monkey D Luffy, comicvine.com
Monkey D Luffy, is the main character in the manga and anime One Piece by comic artist Eiichiro Oda. Luffy is told as a child who aspires to be a pirate king free adventure and sailed oceans around the world.
His ambition to become the king of pirates, can not be separated from the influence of Shanks pirate crew who had visited Fuusha Village when Luffy was a kid. For Luffy, Shanks's pirate crew is a group of great and powerful people who live freely across the ocean.
Promising to surpass the Shanks pirate group, Luffy is determined to become a great pirate king and have his own crew someday. So far, Luffy's journey into a pirate with friends he had recruited on the way, had been involved in various battles.
Monkey D Luffy perang Marineford, aminoapps.com
Various fights both against the navy, shicibukai, and other pirates, has dilakoni Luffy and pirate group Straw Hat. However, did you know that Luffy had never killed an enemy he had ever defeated?
Oda Sensei himself admitted that Luffy had never killed the enemy he defeated. According to Oda, in the era of pirates, everyone has their own beliefs and Luffy has undermined their belief by defeating him.
"Why did Luffy not kill? In this era, people put their lives on their beliefs, their stance and their battles.When Luffy goes to war, Luffy destroys the beliefs of others, and when the enemy's convictions are ruined and lost, they feel the same pain I think that for this pirate, killing or not killing is unimportant, but the most important thing is win or lose, "Oda Sensei explained referring to the question on SBS Volume 4.
Luffy vs Katakuri, deviantart.com
From here we get the answer why Luffy never killed his enemies. In the One Piece story, the collapse of a person's belief is tantamount to death for that person.
That is the reason why Oda created Luffy's character that never killed the enemies he had ever defeated.