I spend a lot of time in my job looking at visual research, and particularly visual research of an architectural nature. So as I play games I often find bits of the game world that remind me strongly of something in our own world—a place, a building, a particular photo or painting. Now, I’m certainly not saying that these are actually the images that the game designers had in their own minds as they went about creating these amazing worlds; but they might have been, and certainly they are things that their work reminded me of.
A lot of the power of these games is that they are similar enough to our own world and history, mythologies and stories to feel recognizable and true, while also being different enough to create an observational distance that might allow us to see previously unnoticed, or unremarked-upon, things. Visual research is one way of recognizing those similarities and strangenesses.
The Elder Scrolls Online two-handed sword in the Argonian style is, like the Argonian clothing, armor and architecture, heavily influenced by the ancient Aztecs. The 2H sword is clearly based on a maquahuitl, with some modifications and developments as it advances in materials and levels.
Like the European sword, they came in two varieties – one handed and two handed. Made from wood (usually oak), they were about 3-4″ wide and 3-4′ long. The two handed versions might be slightly wider and as tall as a person. Embedded in the edges was obsidian (volcanic stone) or flint. The maquahuitls were incredibly strong, and the Spanish claimed they could chop the head off a horse with one blow.
from Aztec-History.com
But it also has some echoes in lesser-known blade shapes from European sword history.
Styrian Armoury, Graz, Austria 
That last one is the two-handed sword of the Bavarian Prince-Elector Maximilian II (1689) courtesy of @MuseumArchive. It’s even more crocodile-toothy than the in-game Argonian blades, but I like to think they could go there. It’s also evocative of the Barbaric (Reachmen / Forsworn) style:
from eso-fashion.com 
Forsworn sword, Skyrim
On the subject of Argonian motif weaponry, how about them two-handed mauls…
Styrian Armoury, Graz, Austria
The staff of Abnur Tharn and this scythe-like polearm weapon:
Styrian Armoury, Graz, Austria
And let’s not forget:
You see those warriors from Hammerfell? They’ve got curved swords. Curved. Swords.
Skyrim, every third Guard NPC
pies & heavy armor 