[HoneyBadger]

Actually, they match the historical images of vikings. I don't believe there's a whole lot of information on Jotun arms and armour. Some did apparently use swords (Surtr, for instance), but that doesn't necessarily mean a whole lot.

And you can't apply human physiology to Niefelheim giants, because they're fashioned from ice, and primordial, semi-divine beings, as well. You might imagine them, for instance, with entirely different molecular structures-stronger cells, harder, denser bones, better muscle-bone architecture, etc. Plus, even a humanoid of gargantuan size is going to have a different body structure than an average sized human. Gigantopithecus, for example, although very similar to humans, compared to most other animal species, also has a very distinct anatomy, in part, due to it's enormous size.