Very cool character! Though I noticed a few errors...
: My name is Ironsoul and if you couldn't already tell I
: am a Myrmidon of the Cath Bruig race.
The Myrmidons weren't Cath Bruig. There were a warrior race, likely kin of the Berserks.
: I wear a large full-length black cloak over my entire
: body and tend to keep to myself since I cannot
: communicate well with others. I speak only the Bruig
: language and can therefore only communicate with
: veterans of the Heron Guard or the learned and
: educated scholars of the land.
Bruig is the language spoken by humans throughout civilized world. All sorts of once-humans (such as undead) and human-made creatures (like Stygs) speak it as well. Dwarves, Fetch, Forest Giants, Ghols, Mauls, Myrkridia, Trow, Berserks, and fir'Bolg all speak it in addition to their native tongues.
: I was born in Stöng in the year 2154 A.E. At the age
: of 18 I joined the ranks of the Myrmidons and soon
: learned the ways and code of the warrior. When I was
: in my mid-late 20's an evil force began to consume our
: land. At the head of this darkness was a figure who
: called himself Ashfear, which translates into Balor in
: the modern tongue.
I wouldn't say "translates". Perhaps "He called himself Balor, but we knew him as Ashfear" or some such.
: There were others with him, his generals if you would
: call them that. And in return for our service our
: leader Bonespliter was appointed to such a position.
Remember that Bonesplitter is The Lurker, as far as we can tell. You sure you want the Myrmidons to be lead by a woman? Bonesplitter isn't even a proper Myrmidon name - no Myrm names are "[something]er" as in someone who [does something]. Instead they are things like Boneslaughter (not Boneslaughterer) and Bonesplinter (not Bonesplinterer), Fleshtear (not Fleshtearer) and Fleshbite (not Fleshbiter). So "Bonesplitter", the Lurker, is likely not even a Myrmidon.
Otherwise, very cool character!