Well, something related to it came up elsewhere on the forums, so here's my name's origin story.
It wouldn't be innacurate to say that Pokemon was the first fantasy series I really got into, and thus my perceptions of what fantasy creatures entail was coloured by it. During high school, when I was getting into various fantasy books and tabletop RPGs, my preconceptions that things like Skarmory and Aron were standard fare clashed with a lot of material that labeled metals as 'unnatural' and had them separate from the magic system and creatures that made use of it. By this time, I was already well aware of facts like it being a giant metal ball protecting all of us from solar wind and some metals being findable just lying around, because being a science nerd means I know some random stuff. I was even less impressed when I learned the origin for some of the myths about iron repelling magic could have originated from bronze-age people being sore losers (i.e. they attributed being beaten by iron weapons to the iron dispelling their aid, not to the fact that their metallurgy was outclassed). So when I was joining a forum for my preferred tabletop RPG (that incidentally did not let the main nature-based class wear metal armour), I took the name "The Sideromancer" as a bit of protest against that trope, with the 'The' taking a stab at the rarity of metal-based magic. Since then, I've alternated between that name (usually without the 'the') and its anglicized form, which I'm using here.