Thorfinn is the main protagonist of Vinland Saga. Throughout the story, Thorfinn witnesses events that shape his character. As a kid, he was nothing more than an innocent boy, who grew up in a loving family. Unlike other kids, Thorfinn wanted to be a strong person like his father.
Sadly, Thorfinn's entire life came crashing down when he snuck onboard Thors' ship. He became a ruthless killer, who didn't hesitate to murder anyone. Thankfully, Thorfinn didn't remain the same person forever. Over the course of the series, Thorfinn was involved in various events that shaped him into the person that he is.
This list contains spoilers for the Vinland Saga anime
6 Thors' Death
Thors was Thorfinn's father, and he was one of the strongest characters in the series. He gave up his life as a warrior to be able to live happily with his wife and family. Thors managed to stay under the radar for many years, but eventually, Floki found him.
Thors was ordered to fight for King Sweyn, and he couldn't turn down the request. Little did he know that it was just a ploy to kill him. Thors took a few young men from the village and set out. He wasn't aware that Thorfinn had managed to sneak onboard the ship. Thorfinn had good intentions, but it was because of him that Thors had to surrender to Askeladd. Naturally, this event left a huge scar on Thorfinn's mind.
5 The First Kill
After witnessing his father's death, Thorfinn's heart was filled with vengeance, and all he wanted to do was kill Askeladd. Sadly, at the time, Thorfinn was too weak, so he had no option but to travel with Askeladd's group. When the band of mercenaries arrived on an island, Thorfinn decided to follow them.
During the short time that he was on the island, Thorfinn ate scraps to stay alive. On the other hand, Askeladd and his group continued to pillage, but they were attacked by soldiers who were ruthless. They didn't hesitate to attack Thorfinn, but luckily, Askeladd managed to arrive just in time to save him. This incident made Thorfinn realize that he couldn't continue to be passive. Moments after surviving a scare, Thorfinn was attacked again, but this time he decided to fight back. He stabbed the man and killed him. This was a massive turning point in his life, as he had officially stepped into the world of warriors.
4 Teaming Up With Askeladd
Thorfinn continued to be a part of Askeladd's mercenary group, as he wanted to challenge the latter to a duel. Thorfinn was given many dangerous missions, which he completed without any problems. His growth as a fighter was staggering, but he still couldn't defeat Askeladd.
Toward the end of the first season, Askeladd was almost killed by Thorkell; however, Thorfinn stepped in at the right time. He challenged Thorkell to a duel, and as expected, the veteran dominated the fight. Seeing Thorfinn battle with such zeal, Askeladd decided to help him. Initially, Thorfinn refused to listen, but Askeladd wasn't backing off either. In the end, Thorfinn had no option but to go along with Askeladd's plan to knock out Thorkell. To Thorfinn's surprise, the strategy worked, and it saved their skins. Seeing Thorfinn after the fight, it was clear that he had evolved both as a fighter and a person.
3 Seeing His Enemy Die
For the entirety of the first season, Thorfinn was solely focused on killing Askeladd. Nothing else mattered to him. Thorfinn expected that he would be the one to kill his father's murderer, but life had other plans for him. When Canute's group traveled to meet King Sweyn, no one expected things to descend into chaos.
As Askeladd stepped forward to receive his honor, Sweyn blackmailed him. Having been left with no other choice, Askeladd lobbed off the king's head, prompting the soldiers to attack, but none of them could even scratch him. Eventually, Canute stepped up and stabbed Askeladd. Thorfinn could only stand there and watch as these events unfolded before his eyes. He approached Askeladd and kept shouting that he couldn't die before their duel. In his last moments, Askeladd asked Thorfinn what he planned to do with his life. Unsurprisingly, Thorfinn had no answer, as he had never thought about it. Needless to say, the final conversation that he had with Askeladd proved to be life-changing for Thorfinn.
2 Being Sold Into Slavery
Askeladd's death shook Thorfinn to the core. For the most part of his life, he only had one goal: to kill Askeladd. When his enemy was killed by someone else, Thorfinn fell into despair. Shortly afterward, Thorfinn ended up as a slave on Ketil's farm.
Thorfinn found it difficult to adjust to the lifestyle, but with time, everything started to fall into place. Thorfinn became a different man, and he lost all the rage. From time to time, Askeladd would appear in his subconscious and talk to him about the old times, but Thorfinn stayed strong.
1 Meeting Einar
Einar happily lived with his family in a small village, but it all went up in smoke when the Vikings attacked. Einar's family was slaughtered, and he was taken as a slave. He thought of running away many times, but he knew that survival wouldn't be possible. Einar was eventually bought by Ketil, who took him to his farm.
The first meeting between Einar and Thorfinn was not very eventful, but as the story progressed, the two became well acquainted with each other. Einar's positive attitude helped Thorfinn when he was struggling with his inner self. With Einar's continued support, Thorfinn was able to find his path and change his ways completely. As the two were working together almost all the time, it is difficult to single out just one moment that showed Thorfinn's development.