Vostroyan Firstborn
The Vostroyan Firstborn are RUSSIAN SPACE STRELTSY/UKRAINIAN SPACE COSSACKS. They use old weaponry they consider valuable. They wear richly colored coats and large fur hats.
Vostroyans are experts at urban warfare and firing drills. So they are like the Mordian Iron Guard with less dress up bullshit. IT'S NOT BULLSHIT, IT'S TRADITION YOU DICKNOGGIN.
Their name comes from the tradition of the first-born son of every family (from the commoners to the nobles) serving in one of these regiments, and they bear the name with pride. GLORY TO THE FIRST MAN TO DIE.
Culture
They like their mustaches. Their coming of age is sprouting a four foot long mustache and goatee combo. They like them so much that if you don't have a mustache you must therefore lack genitalia. Presumably Vostroyans drink a lot and dance like this: [1]
Typically they all look like so: [2]
Vostroya
Their home world is really cold. Vostroya isn't a Forge World nor is it an Imperial Hive World, so it falls in between and gets the award of being an Industrial world. BUT AT LEAST THEY'RE USEFUL UNLIKE THE DICKS IN BLUE.
They should be on the look out for the birth of Space Peter the Great.