Content Warning: This article contains a discussion of some dark and gory themes.
Ragnar's death in Season 4 of Vikings had many fans worried. Would the show survive him? Their concerns were warranted since the departure of a main character can be a difficult hurdle. However, there were plenty of other stories to tell in the show.
While Ragnar's sons did a good job of filling in the void he left, the characters introduced after his death were also instrumental in moving viewers past the Lothbrok era. It can be argued that the series got even better after Ragnar's death since the screen-time pie was well distributed rather than being given to only a few characters.
White Hair
White Hair was quite the daunting henchman. The leader of Ivar's bodyguards did more in the 10 episodes he appeared in than what other series-long characters did. His numerous transgressions included killing Bjorn's son Hali during the Grain Raid and beheading the shield-maiden Skadi.
With a name that was fitting, White Hair was relentless. He attacked Lagertha's village twice, leaving plenty of victims in his wake. He was also very capable. The best example of this was when he sneaked Ivar out of Kattegat right after Hvitserk, Bjorn, Gunnhild, and Harald gained access to the city thanks to Freydis' betrayal. It took a better opponent in Lagertha to kill him.
Oleg
Only a special kind of villain would dance as his brother died. That's what Prince Oleg did when he poisoned Askold. And while most people become friends after bonding overs shared hobbies, Oleg and Ivar bonded over something very bizarre they had in common—they both murdered their wives.
Oleg was a very intense and bloodthirsty figure. He kept his wife's coffin, and when he murdered the guards watching Dir, he gouged out their eyes before serving the heads to Igor and Ivar at the dinner table. The Machiavellian ruler was very willing to murder his way to the very top. Interestingly, he was very keen on spreading Christianity too.
Freydis
Freydis was an expert at "gassing up" people. She constantly showered praises to her husband Ivar, making him feel like the most important person in the world even though he was evil. She was brave and cunning as well. In her first-ever scene after she got captured in the Battle Of York, she proved to not be afraid of the intimidating Ivar, something that impressed the man.
She lied to Ivar that the gods had great plans for him. This made him spare her life. Given how often she poured excessive praises at Ivar, there was the presumption she'd be loyal forever. That wasn't to be. Her treachery became even more evident when she betrayed Ivar, allowing Bjorn, Harald, and Hvitserk to overthrow him.
King Olaf
Olaf was the ultimate opportunist, quick to jump to whichever he thought he thought was the winning side. At first, he wanted to form an alliance with Ivar to invade England, but when Ivar sent Hvitserk to talk to him, Hvitserk convinced him to join him and attack Ivar instead. Olaf also appeared as the cowardly king as he kept doubting whether they'd win against Ivar. Luckily they did.
His cowardly moments aside, Olaf proved to be the master tactician when he poured oil over water and set it ablaze, preventing Bjorn and his men from swimming into the harbor of the Tamdrup. He should also be credited for trying to unite Norway under one king. Live by fire, die by fire? Olaf's love for flames saw him die the same way when Igor burned him alive.
Kjetill Flatnose
Played by WWE superstar Adam "Edge" Copeland, Kjetill was one of the few men who were eager to leave Kattegat and accompany Floki to Iceland, despite Lagertha's orders to not do so. With a tough-guy appearance Kjetill looked like a threat at all times. And a threat he indeed was.
He massacred Eyvind and his family when they were starving and too weak to fight back. He also proved merciless when he decapitated Helgi without hesitation. Perhaps the most notable thing about Kjetill was his sense of self-importance. He acted as if he was the leader, even though he'd be nothing if not for Floki.
Princess Katia
It's not often for two different characters to be played by the same person but that was the case for Princess Katia and Freydis (both were played by Alicia Angeson). After killing Freydis for betraying him, Ivar was shocked when he met Katiam, the Russian Princess. That's because she looked exactly like Freydis.
What made Katia an interesting character was the mystery behind her. Viewers were kept guessing whether she was real or just a figment of Ivar's imagination, stemming from his murder of Freydis. Despite series creator Michael Hirst hinting that she was an imagination, things became more complicated when she became pregnant with Ivar's child. The mystery remained until the end of the series.
Ingrid
Ingrid appeared in only the final season but her character development was very rapid. This weeded out any boring moments that might have surfaced for her. She was immersed into the proceedings when Bjorn had an affair with her then took her as a second wife, something Gunnhild wasn't too troubled by. Harlad, on the other hand, wasn't too happy because he had offered her the chance to be his only wife.
Things took off for Ingrid from there. In no time, she became a skilled shieldmaiden, helping Bjorn in the Rus War. After Bjorn's death, there was another shocker. Erik discovered she was a witch when he found her performing rituals at her husband's grave. In a perfect example of taking care of the witness, she turned Erik blind before focusing on taking over the throne.
Gunnhild
Gunnhild's status as one of the strongest shield-maidens made her instantly likable. She was one of the few people who managed to hurt Bjorn on the battlefield. She was not only great at comforting people but was quick to forgive too.
When Harald was stressed and feeling vengeful after the death of Harald, she encouraged him, assuring him that he'd find another wife someday. She also consoled Bjorn when his mother disappeared. More importantly, she never hesitated to challenge Bjorn whenever he went out of line.
Othere
Like Katia, Othere The Wanderer was fascinating because he was mysterious. There have been discussions on whether he was real, a metaphor, or a god. Since the show never really portrayed gods, only two options are left.
Othere talked a big game, claiming to have found the Golden Land, though it wasn't how he had hyped it. He was also a suspect in the disappearance of Floki. This was confirmed when Floki suspiciously stared at him upon being found. Othere was a liar, too, as it was later revealed that he was a Christian monk named Athelstan.
Erik The Red
The Rus expedition was one of the best in the series but the intelligent Erik was the first to identify the Rus flag. Erik was generally tough, having served as a mercenary in his past life.
He had a reputation too. Harald decided not to kill him after Olaf told him who he really was. To top it all, he was one of the best soldiers to ever step on the battlefield. He slew more Rus soldiers than any other characters. Erik also proved to be a good leader when he was given the task of protecting Tamdrup using Bjorn's forces. It thus wasn't surprising when he became King of Kattegat.