Alright, where to start. 

Well, the royal families of UMBRA each have their own personal 'honor guard' as it were. The Onyx family prefers things of a more magical nature. Their defenders are the Blackguard, about three dozen heavily armored mage-knights. 

The big thing about UMBRA is it's a very selfish country that prizes individuality and progress (both magical and technological), above things like order or discipline. As such loyalty to just any Czar is ridiculous, but loyalty to a particular family is not. Chaos and ambition are UMBRA's hallmarks, for good or ill.

As such, it has an extremely disorganized military, each family possesses its own small army that could potentially add up with every other families to make a real one. small groups of heavily trained men are the norm. 

There aren't even proper numbers, battalions, or the like. they just take like groups of soldiers, give 'em a name, and that's it. 

In fact, the 903rd actually sounds more like it a Terran military organization than anything. A group of ordered professionals willing to do anything for their master, yet unconcerned with morality. 

As for alignment, Sevarious lacks that selfishness, greed, and ambition that identifies those of dark affinity. He sounds more like earth, or water.

As for gear, slightly too advanced. Okay, way too advanced. the stuff you listed exists, but I can't let you have it at the start. Maybe they confiscated his best gear when he was relieved from duty (and they would, there's like what, 400 suits of plasteel armor in existence?) The rule for tech is that if it's more advanced than dieselpunk (it's like steampunk WWII) you can't start out with it. That would be like letting people start with time travel spells. (though the shield looks balanced enough). 

and don't feel too bad, I grill everyone like this (except TurboTuber, he's a fucking potato and thus awesome)