I ran into a few npcs that wear this armor style but I could not get any information about it. The npcs carrying this armor are always from the Fighters guild. The style itself looks a lot like soul shriven style, only it is more polished and not rusty. I like the plain look the cuirass has and the upper pieces of the armor look a lot like the iron armor from Elder Scrolls: Oblivion.
My mistake for not pointing out for the last two pictures that I was just pointing at the pauldrons, also I am aware that the dunmer is wearing orc medium but the cuirass seen on other pictures is not breton style. Iron breton armor is composed of a lot more leather stripes on it and breton steel and breton orichalcum are more bulky and shiny.
Guy on the top is also wearing Akaviri legs and possibly Akaviri boots, not 100% sure though.
He is wearing Imperial low level medium armor, boots and legs. Upper body is the plate (presumably Breton) you can find at levels 1-5 or maybe just in Coldharbour.
The pieces I am curious about are cuirass, pauldrons and gaunlets on the first picture. The pauldrons and gaunlets have the shape of the soul shriven pauldrons and gaunlets and not breton style and pauldrons are completely metallic unlike breton pauldrons. Also at levels 1-5 in Wailing prison you find soul shriven pieces that are rusty and dirty. Also if it is low level breton armor how come I cannot just craft it?