#dianite

mia gives a more feminine vibe (imo at least idk how many would agree with that) but because of that vibe, mianite being a masculine character probably chose not to go by mia as much as possible (though i dont doubt, if this is the case, ianite and dianite calling mianite 'mia' to tease him in a sibling way at every opportunity)

and if ianite went by ia, well, thats just ai backwards, and i would hope that, at the very least, despite her objective countless flaws, ianite doesn't support ai. (but also how tf would 'ia' be pronounced if someone just randomly saw it out of context???? anyone outside the fandom would just look at it and go "wow, two vowels, and thats enough for people to scramble over" at least, i think, idk. trying to think about an outsiders perspective is hard when ive been a fan of the series since it came out)

whereas dia for dianite works perfectly as a nickname, because loads of names and things start with dia, it could just be one of those common nicknames dianite uses to be more interpersonal with his followers, (similarly to how tom is generally short for thomas).