[@Ammokkx] Alright, time to roll up the sleeves.

I am going to ask you to bring the ages up a little. Warrior people or not, they wouldn't be sending children into battle. They'd be fifteen at the extreme least. Nor do I think that the infighting would be as constant as the Guldbrand are; it would mostly be raids for supplies/defending against raiders, and over the squabbles of the chieftains.
While Ragnarok does make sense according to what we discussed in PMs, it could be a little too OP, and there is historical evidence to support that beserkers would in fact be able to gather this kind of blood-fury, negating its being magic. That isn't to say this can't be the final choice, but do you have any other considerations for Destin's spell?