... Okay, I'm not an expert, but since it's been nearly two weeks, I'll put my two cents in.
The rectangular scutum and lorica segmentata line up approximately with the Principate period (late 1st century BCE to late 3rd century CE). If someone with more familiarity with segmentata can assign this example to a subtype (which I don't assume it can be, seeing as the panoply as a whole is clearly fantasy and labeled as such) then that could narrow down the period a bit.
I'm tempted to remark on the fact that he's wearing his sword on the left (associated with centurions in the early Principate), but the evidence is somewhat ambiguous --
see here.
The animal skin over the helmet (a real one, not metal!) is broadly associated with signifers. However, they would also have a signum, obviously, and supposedly a round shield. Also, he's clearly an infantryman, whereas I've always read that the mask helmets are thought to be cavalry types. Of course, there may be a lot that I don't know, but on the whole, this all makes it look to me like trying to figure out the character's rank or unit vis-a-vis real life would be difficult if not futile.