Them Ixal arms...

[Naraku_Diabolos]

Why is one bigger than the other? I remember seeing someone post something like this a good while ago, but I don't remember seeing a Dev answer why the Ixal models like this. Is it due to how they evolved (in-game lore) or how the character model was created to hold a shield?

[Fenral]

Don't they have padded armor over one arm?

[Anonymoose]

Don't they have padded armor over one arm?

They do. At a casual glance, it might look like they've strapped plate over a larger, differently-colored arm, but the whole thing is one puffy sleeve.

[Nalien]

Lets not rule out the obvious answer here;

I hadn't actually noticed this. Some of them (mages?) have the same arm, but yeah, the ones which seem to have a bigger right arm are just armored up. Can see it somewhat more clearly in the concept art;

[Bombast]

As others have said, its a glove/arm armor.