Punching both Basim and Sigurd will lower your loyalty with Sigurd and affect the ending. If you choose not to punch Basim or Sigurd then your loyalty will stay the same.
If you punch Basim and Sigurd:
Sigurd will leave with Basim, calling him friend, while further scolding Eivor and casting doubt on their wisdom. Sigurd will remember the outcome of the argument, and will let it negatively affect his decision making later in the story.
During the argument, Eivor is given dialogue options of “Take Breath”,”Punch Basim”,”Enough of This” and “Punch Sigurd”. If Eivor punches either Sigurd or Basim then that counts as a Sigurd Strike. Punching neither is the honorable choice.
You should choose to (Take a Breath) as punching Basim will anger both of them and Basim will comment that your lack of control over your emotions is a problem. Choosing the second option here can also affect the ending so punch Basim at your own risk.
Doing three or more of these will lead to Sigurd leaving for Norway but if you have only done one or two, you'll be fine and he'll stay in the settlement with you for good. Plus, he breaks up with Randvi so you're free to be in a relationship with her.
In the climax of 'A Brewing Storm' you and Dag finally battle it out. After defeating him, you should 'Give Dag his axe' as a final gesture of respect. Even though he can be quite the annoying bug, doing so will keep Sigurd happy as Dag was, after all, a Viking who fought by your side for most of the campaign.
You must wait until they are separated to avoid impacting your loyalty with Sigurd. In mission Blood from a Stone, you must prevent yourself from punching Basim and Sigurd. In mission A Brewing Storm, give Dag his axe after you defeat him in battle to avoid impacting your loyalty with Sigurd.
Sigurd can't hurt you so there's really nothing to this boss fight. Just wack him a couple times with whatever weapon you'd like. Seriously, he can't hurt you. Let him try — he'll hit you and knock you down, but it won't do any damage.
After being rescued from Fulke, Sigurd is a changed man that is now highly irritable and seems extremely arrogant on the topic of his bloodline which he claims lets him see things. One of these things is finding out that Randvi cheated on him with Eivor if Eivor decided to sleep with her in the Taken For Granted quest.
Turns out that Eivor is the incarnation of Odin, yep, got that, but Basim is the incarnation of Loki, yes, that trickster god, and he's angry about Odin killing his son, Fenrir.
If you break up with Randvi after the first encounter, your actions won't count as a Sigurd Strike and nudge you towards the Good Ending. What's more, if you'd rather not betray Sigurd, all you have to do is wait for the story to progress as the couple will end up separating down the line (40 hours into the story).
If you sided with Sigurd enough, Sigurd will name three times that proved Eivor's loyalty. If so, Sigurd will then step down as jarl and name Eivor the new jarl of Ravensthorpe. Once they return to Raventhorpe, Sigurd will make the announcement and Ravensthorpe's people will celebrate the decision.
Eivor steals the wealth from Styrbjorn to take with them to England. Eivor starts a relationship with Randvi (Sigurd's wife) before she and Sigurd separate. Eivor loses their cool and ends up punching Basim and Sigurd during an argument in Oxenfordscire. Evior does not give Dag his axe in their last fight.
Strike #1: Take the Cargo with you in the prologue. Strike #2: When you get the opportunity, romance Randvi. Strike #3: During the “Blood from a Stone” quest punch Basim and Sigurd when you have an argument. Strike #4: When you beat Dag in a duel during “A Brewing Storm” quest, do not give him his sword back.
Let her be exiled: You'll strip her of her titles, names, and land, removing the right for her to rule or live in England. She'll threaten to hunt you down and kill you as soon as she's able. Let Geadric look after her: You'll commend her for fighting with honor and pride, but pass her over to Geadric for punishment.
Fulke also admitted that Sigurd is a reincarnation of the gods from before. After leaving Basim and Eivor, Fulke ordered her guards to kill them and then bring their bodies to Canterbury. Fulke and Sigurd were apparently traveling together, as Basim and Eivor sought to find them in Cantebury.
The two remaining sons of Ragnar, Bjorn Ironside and Sigurd "Snake-in-the-eye" Ragnarsson, are nowhere to be found in Assassin's Creed Valhalla.
How Adultery Plays Out With Randvi. Randvi is the greatest exception. In Assassin's Creed Valhalla, all story trails lead to Sigurd. This is ultimately a tale of two siblings, so players' choice in Assassin's Creed Valhalla to sleep with Sigurd's wife Randvi can actually affect which ending players receive.
Sigurd was a skilled warrior and cunning tactican, leading many successful raids before his voyage to England. While quite intelligent with a skill for politics and military tactics, he was easily manipulated by Basim, by playing on his desire for greatness.
While they don't become a full member of the Brotherhood, players learn that Eivor is actually a reincarnation of the Norse god, Odin. Through their past life, Valhalla also reveals perhaps the most surprising villain of the entire game.
If you make 3 Choices against Sigurd (Sigurd Strikes), he will dislike you and leave England to go back to Norway at the end of the game. If you do the opposite and pick the choices in support of Sigurd, he will like you and stay with you in England at the end of the game.
But if you have your heart set on romancing AC Valhalla Randvi, all is not lost. You will be able to hook up with her later on safely, after Sigurd and Randvi break up. This way, you won't upset Sigurd and risk the ending you'll get.
I feel the same way – Eivor professes their feelings to Randvi, and they make love after a little more chatter. Sigurd will eventually find out about this, and that counts as a choice against him. If you make enough of these, it'll affect the ending of the story.
If you'd rather wait until near the end of the story to romance Randvi (thereby giving you the option to romance others such as Petra and Tarben in the meantime), you'll need to wait until Gunnar's wedding during The Forge and the Flame.
You'll need to travel to Hordafylke, Norway, and speak to Sigurd to begin this quest. He can be found in the room right next to the Alliance Map room. He'll be sitting on a table — speak to him and a cutscene will begin.