Starting with his childhood, Kenshin's upbringing was very sad and remorseful. After his parents died from disease when he was 6, he was sold into slavery. When his caravan got attacked, he was saved by his future master Hiko Seijūrō after being protected by the other slaves.
A week after when Hiko returned, he sees that Kenshin already made graves for everyone who died that die. This shows a lot about his kindness towards others. After seeing this, Hiko gives Kenshin his name and promises to train him in swordsmanship. Years later, Kenshin is already
a very strong swordsman, being one of the strongest in all of Japan. This is because the style he was taught was the Hiten-Mitsurugi style, which is the best style for killing one's opponents. After hearing about the war taking place, Kenshin rushed to join, leaving his master.
In only a couple of months he killed over 100 people, earning him the title, Hitokiri Battōsai. While he was in Kyoto he met a women named Yukishiro Tomoe. They got together and lived as a married couple. However, Tomoe was working with the Yaminobu group that was after Kenshin.
After finding out that they used Tomoe, Kenshin went to their leader. As he was going to kill him, Tomoe jumps in front to protect Kenshin, and dies. This fills Kenshin with deep regret and would cause him to leave Kyoto. He would eventually swear an oath to never kill again.
After the war, he became a wanderer, to search for ways to repent his sins. 10 years later, he meets Kamiya Kaoru. After helping her, he ended up living with her. In Tokyo, he meets new friends such as Yahiko and Sanosuke. Kenshin had nowhere to go in life and had no purpose for
his entire existence. He was okay with dying as long as he could protect his friends. But when he met his new friends, these thoughts changed. He didn't want to die anymore because it would hurt those around him. Even though he made his vow to never kill again, Kenshin was still
haunted by his inner scars of his old self. In times of battle, his inner Hitokiri comes out and takes over. He becomes a manslayer when battle gets tough. When he hears about Shishio's plan to take over Japan, Kenshin leaves for Kyoto. He is heavily against Shishio because the
current Meiji era is peaceful. He leaves everyone in Tokyo because he doesn't want them to get hurt. After battling Shishio's right hand man, Sojiro, Kenshin realizes that he can't win without going back to his old self. He then meets his master once again to learn the final
technique of Hiten-Mitsurugi, but he can't fully master it unless his personality goes back to the Hitokiri. But he learns it by getting his fierce personality back with the thoughts of protecting others instead of to kill. He then goes to face Shishio and ends up winning.
A month after the battle, he returns to Tokyo with his friends. He then runs into a man named Enishi, who was Tomoe's brother. Enishi wants to avenge Tomoe by making Kenshin suffer in the worst ways possible. Enishi then kills Kaoru. Kenshin, losing the one he loves most,
is filled with despair. Because of this, he goes to the Fallen Village and locks his sword away. But after hearing that his friend Yahiko is in trouble, Kenshin leaves those thoughts behind and goes to help. After hearing that Kaoru is actually alive, he goes to the island that
Enishi is on to take her back. Because of his past actions, Kenshin finds a new a new answer to how he should live his life. "Vowing to the sword and soul, this life of battles will be followed through". After taking down Enishi he goes back to Tokyo to live with everyone else.
Five years later he has a child with Kaoru and they live happily ever after. In Kenshin's life, his personality and beliefs made great changes and he became a stronger person over time.