For my main's name, it was just me wanting to keep a name that starts with V that seemed to go well with Zvahl. In FFXI, Zvahl was the Shadowlord's castle, and I used to farm most of my gil from there, even after they nerfed gil gains from NPCable items dropped by the demons. It's a castle full of demons.
As for my forum name, it's been my yahoo email handle since I was 11 years old. I used it in 2002~2003 for my now defunct Runescape character. In FFXI in late 03/early 04 I shortened it to Vyre. Vyre Zvahl didn't seem right to me, and I couldn't get any of the Midlander models to look acceptably like my FFXI Hume, so I went with reimagining with a name alteration. Though I would later create an alt that nearly overshadowed my main, many times, named Vyre Vahzl, Vahzl being the word for the Teleport Crystal of Xarcabard, where the Shadowlord's Castle Zvahl is located.
In recent years, apparently some popular streaming girl stole a bunch of FFXI names, and I've been approached by fans of hers before, them claiming I must be a big fan too. Nope. Didn't even know she existed until it was brought up.
Also sometime in the last decade, Runescape made some sort of bat demon creature called Vyres and introduced the Vyrewatch. I would sue them if I had any kind of copyright claim to my name, but I don't.
And I've also met some people who think I'm into some black metal band that came out in the late 2000s/2010s called VYRE but I think one of the letters is a rune? I listened to some of their music, it's not for me.