I based The Myrmidons on those in Greek Mythology whom as described in the Iliad were commanded by Achilles during the Trojan war.
I also played on the word minion, which sounded a lot like Myrmidon.
The term Myrmidon came to mean "hired ruffian" or "loyal follower, especially who executes orders without question, protest, or pity - unquestioning followers."
In the world of "aeron Aether" The Myrmidons are created from darkness by Khronos himself. They are sent down to the mortal world to take out the criminals and other evil doers of the world. They eliminate these evil doers with their pointed staff. The magical staff once impaled into the skin disintegrates mortal flesh from time and space.
I took inspiration from the look of those in Greek Mythology with the shape of the helmet and the spear for a weapon. But J.K. Rowling's Dementors hold some inspiration here also, as Myrmidons are supposed to be an emblem of death and destruction controlled by an outside source with no individual thoughts or comprehension. J.K.'s Dementors make me think of death and the grim reaper and thus the black long hooded coat and magical staff are reflected here.
"A sudden flash of white light came from an adjacent alley way, a hooded being emerged from the light, and as it floated forward the light disappeared. This being had an eerie creeping walk to them, almost as if it was stalking prey...
The being now out of its creeping position, stood as tall as Aether. The being lowered its cloak to reveal its long armoured helmet. Its piercing white eyes, the only feature one could make out from the darkness behind it. It let out an ear piercing screech, but Aether did not flinch. Any other mortal would lose consciousness once this noise penetrated their ear drums. Not Aether, for Aether was not mortal. Much like the being was not mortal."