Concept art of Ustiarius, royal guard of Canterlot Palace in my fan-fiction, The Tale of Two Sisters. Fun fact: Ustiarius is Latin for “Doorkeeper”.
Ustiarius is designed to be a generic royal guard, thus his fairly simple design, accented with some facial hair for personality. The armour designs are just ideas, and I’ve yet to nail exactly what I want the guard armour to look like; it needs to be reminiscent of that seen in the show, with an archaic twist, somewhere between medieval European and Roman. For context, my head-canon for the eras of design go: Pre-Classical Era, aka medieval (current story era) -> Discord Era, aka Roman (think Flash Magnus) -> Classical Era, aka Grecian (I think the comic covered this era) -> Modern (show-style). I’m aware that this isn’t chronologically accurate for humans, but it fits with the show’s canon. You’ll also notice I’ve not settled on Ustiarius’ cutie mark yet either… but I wonder if you can see a clue in the designs.