The "Japanese sense in naming" is a trope because ....the japanese have no naming sense.
Certainly not one that translates well, or at all, into english.
Dunno about the moon runes used, but the name could well use two different kanji for "Iron", each with their own associated meaning(s). As Kanji, famously, do...
I suspect from context the nickname should, at least in english, be something like "cold-blooded blade", or something similiarly cringy, but then you'd have the Purists all up in arms about "unfaithful translation"..
Not that the actual nickname is bound to be any less chuuni-cringy in japanese, given the nature of this manga...