The Blazing Knights (Burning hearts for the Glory and the Dawn)

Born in the Empire of the Holy Flames, the whole order is now spread around the continent, acting as a res publica: not influenced by the single laws of each state, they operate independently.
This, in theory. While the detached battalions, placed in other nations, answer only remotely to the main body, the Blazing Knights in the Empire are widely known as an extremely efficient and lethal anti-magic force.
They're the elites of the army, and the very symbol of imperial power. Nobody can ignore the burning sun on their armour. While wizards often resent the knights as symbols of the policy of control over magic that’s becoming more and more popular, the people of the Empire see them as saviours and holy warriors, champions of all that is good, armed with piety enough to protect the world from the ravages of foul magic.
It's known for them to make a huge use of ivrium, which enhances their abilities and gives a bunch of new ones, but the exact procedure is unknown.
They are known to often offer a substitute for orphanages, and take care of the younger.
More often than not, they join the order a few years later when offered promises of glory and fame, often fulfilled.

“The Blazing Knights are the royal emblem of the Empire’s army, often looked at for examples of virtue and patience.
In reality, the militant arm looks first for skilled warriors with unshakable single mind purpose, with a flawless moral center as a secondary concern. Knights must carry out their duty with an emotional distance, and the Blazing Order prefers soldiers with religious fervor and absolute loyalty over paragons of virtue who might question orders when it comes time to make difficult choices.
The knights' power derives from the substance ivrium, a mineral believed to be the raw element of creation. While magic users use ivrium in their arcane spells and rituals, they ingest the primordial mineral to enhance their abilities to resist and dispel magic. To enhance their abilities is a cool side effect, too.
[Love keeps telling me not to go too into my personal opinion of them, but I want you, reader, to ask yourself why if I smoke Cloud’s breath I’m a dangerous and dirty addicted, but if “someone” gives the most powerful drug to kids it's a saint.
With love, Nemo]

Taken from: “Wonders and Wanders of Two Friends: A tales from the Empire” by Loveday