The Duke wore the same get up, except, his was an enchanted armor, giving better protection than what the Guardian of Hex had, while blocking Magic more effectively.
Of course, the Guardian of Hex also prepared for Spells being thrown at their direction. They are not amateur after all. However, they did not have enough funds to afford a full-on enchanted armor like the Duke could.
Instead, they wore a special accessory in the form of a necklace. One that create a simple anti-Magic barrier, weakening Spells thrown at their direction. Not the best in defending against any Spells, even a simple one, but any form of protection is better than none.
Besides the Duke, General Lazil wore the same get-up as Duke Phorus, except like decorative. The younger man's armor lack certain detail like the Duke had, which make sense considering the difference in their status.