This is a very interesting question, and the first one that I believe I have the expertise to offer a sufficient answer on this sub.

I am now in Law School, but I have a degree in History, and I wrote my undergraduate dissertation on this time period. In fact, I was inspired by Bernard Cornwell’s “The Saxon Tales” which is the book series that The Last Kingdom adapts.

In short, the answer to your question is: No. The Danes and other Nordic peoples were probably not as warlike as is depicted in the show, nor were they only influenced by the desire to die in battle. However, it’s important to note that we simply do not know for sure, as there is an extreme lack of sources from the Nordic perspective.

The sources we DO have, like the Anglo Saxon chronicle are from the Anglo-Saxon perspective and typically relate the military and political developments of the time, and there is likely an agenda behind its portrayal of the Danes. The Anglo-Saxon chronicle was mostly written by Christian monks and was heavily influenced by Alfred the Great. By painting the Danes as vicious and devilish invaders, they could garner more support for their campaigns against them- from their own populace and their Christian neighbors.

Moreover- the Chronicle had a heavily pro-Christian agenda that anybody could glean from reading a few entries. Because many of the Danes during the early Viking Age had not yet converted to Christianity- the Chronicle’s portrayal of them in such a violent form was likely influenced by theological debate, and Christian views of Paganism.

In short- the reason we perceive the Danes and other Nordic peoples as innately violent is that we simply have very few records of their own perception of the Viking Age- and most of it is written by their victims. Another important thing to note is that the Danes lost, and Alfred’s Line/ Christianity was successful in rebuffing their invasions. So, violent portrayals of the Danes serve as a means to justify that military campaign and conquest.

Now for the few pieces of evidence I have come across in my research that contradict this theory of innately violent Danes.

First, raiding was not a characteristic unique to the Nordic people. In fact, the Anglo-Saxon’s frequently conducted raids against the Welsh, Scots and Danes. (And vis versa). To my recollection, the Chronicle actually does a decent job of noting these raids from both sides as well. So, the idea that the Vikings suddenly brought death and destruction is likely a concept formed out of the previous biases discussed. However, there is also something to say for the fact that while raiding may not have been unique to the Danes, they may have been the best at it. As their boats allowed them to sail upriver, raid, and escape before help arrived. This success probably also feeds into that perception of violence.

Secondly, we know that the Danes and other Nordic peoples were not in the British isles and elsewhere simply to raid and cause Havoc. They were granted the Duchy of Normandy which gave rise to William the Conqueror and the de Hautevilles, and they established Kievan Rus in modern day Russia. Most important, however, is DNA evidence which shows extensive Nordic influence in the British isles. (Peopleofthebritishisles.org has an excellent rundown of this). This demonstrates that the Danes were not merely in the British isles to rape and pillage, but they intended to stay. The influence of Nordic DNA on the modern British population is simply too significant for the populations to not have meshed and assimilated.

Finally, to your last question about the quest to die in battle, the Danes were not very interested in pitched battles. A large part of the reason that the Anglo Saxons were successful in driving the Danes out of England was the fact that the Anglo Saxons built burns, or fortified cities, to protect themselves from raids, and to force the Danes into a pitched battle. Given the opportunity to raid or fight a pitched battle- the Danes frequently chose to raid. Had they been primarily interested in dying in battle to reach Valhalla, it is almost certain that they would have been more reckless in their engagements. In fact, their caution and ability to quickly engage and disengage was a significant factor leading to their success. This means that rather than fighting with the intent of dying in battle, Danes and Vikings fought for plunder/economic purposes instead.

In any case, besides the fact that the show is dramatized for entertainment purposes, the Danes were probably not as violent as they are normally depicted. That isn’t to say that they weren’t violent at all, because they certainly were, but they also likely had motivations and intentions beyond mere killing. Unfortunately, the true extent of those motivations are likely lost to history, but the History Channel’s theory that those motivations were partly to attain more farmable land may have some credence.

Apologies for format as I’m writing from my phone.

Sources as loosely listed chronologically:

The Anglo Saxon Chronicle. Avalon.law.Yale.edu

Asser’s Like of King Alfred (trans. Albert S.Cook)

Justin Pollard “Alfred the Great: The Man Who Made England”

Paul Hill “The Viking Wars of Alfred the Great”

Alexander Rumble and David Hill “The Defense of Wessex”

Sarah Foot “The Making of Angelcynn: English Identity before the Norman Conquest”