For example in Egils·saga Skalla·Gríms·sonar,
Kveldúlfr and his crew of vikings are called ‘shape-powerful’, a term that usually means either shapeprojecting or shapeshifting. But he himself is specifically said to be ‘going-berserkr’. During this particular attack, he is still wielding a battleaxe with excessive force while berserkr. So, since he still has human hands, it is clear enough his physical body didnt transmogrify into the shape of wolf. This is a case of mentally exhibiting the identity of a wolf.
As such, ‘going-berserkr’ is a subset of being ‘shape-powerful’, or in any case they part of the same concept within the Norse worldview.
Note, Kveldúlfr is a nickname that literally means ‘evening wolf’. He got this nickname because he was known for being ‘hamrammr’. The context is ambiguous, but apparently he was known to often take on a wolf form after the sun set, by outofbody projection or perhaps by bodily shapeshifting. Perhaps these episodes were also only transformations of personality. But whatever its exact effect, it is explicitly identified as ‘shape-powerful’.
Thank you for the citation. You're right that the terms "shape-strong" and "berserk" occur in close proximity there. However, I think a close reading shows that they are actually being
distinguished rather than
equated.
First, a quibble on the matter of Kveldúlf's name: his given name is "Úlf", only the "Kveld" part is the nickname, and the saga states it's because "he was an evening sleeper". This doesn't really matter, because he
is unambiguously described as "hamrammur", but given how common a name "Úlf" is, it seems like a stretch to cite it as evidence here.
Now, berserkers. The saga does not call Kveldúlf a berserker or say he enters berserksgang. In Chapter 1, in which his name is explained and he is called "hamrammur", Kveldúlf's
comrade Kári is stated to be a berserker -- but Kveldúlf himself is not. This wording seems very unlikely if Kveldúlf is supposed to be a berserker. You don't say "Bob had a friend who was a doctor" if Bob is also a doctor.
Then in Chapter 27, it gets
really close.
"It is said that those men who are hamrammir, or those who have the berserksgang upon them, that [they get tired]. So it was with Kveldúlf, that when the hamremmin went from him, [he got tired]." If these sentences stood on their own, I would be tempted to interpret
"or those who have the berserksgang" as a gloss of
"those men who are hamrammir" and concede this point to you. But having already seen the distinction between Kveldúlf and Kári, I'm not sure they're supposed to be read that way. An alternative reading presents itself:
"those men who are hamrammir" and
"those who have the berserksgang" are two different groups of people whom the text is comparing. "It is said of those who are in medical school, or those who are in law school, that they study too hard." Note, again, that when the saga turns back to Kveldúlf in particular, it uses the term "hamrammin" and does not call him a berserker.
Look, cards on the table here: my personal estimate is that you're probably close to the mark on the significance of berserkers. I don't think they were shamans
per se -- they don't show any sign of fulfilling a spiritual social function in these sagas, and seem strictly to be elite warriors -- but with all the animal motifs surrounding them and the attribution of abilities which border on the supernatural, I'd be surprised if the concept didn't have some basis in an earlier animal-magic tradition. And a connection to this other animal-magic tradition of hamramm does seem like an eminently reasonable speculation.
But it is still speculation. And when you are speculating, that is when it is most important to read the primary texts carefully and skeptically, to make sure you don't fall into confirmation bias. We are talking about an ancient culture which, for all its modern popularity, is still in many ways mysterious to us. On the religious and spiritual beliefs of the Norse, we have surprisingly few hard facts (and whatever those facts were, they doubtlessly varied over the hundreds of years and thousands of miles across which the Norse ranged). So when you state hypotheses on the subject, even plausible ones like berserkers being related to animal magic, you need to do so with appropriate caution. It is highly misleading for you to flatly declare concepts and definitions and taxonomies as if they were absolute truth straight out of some nonexistent pagan catechism.
The D&D Barbarian class is designed, at least partially, with the Norse descriptions of the Berserkr in mind.
And that's really the extent of my point. So why try to shoehorn berserkers into the druid class?