I thought it sounded cool. Strangely, I don't like either of the words Zion or Knight, but when you spell 'em like Xion Night they suddenly become awesome.
Aside from that, no meaning.
Used to be Archblade Swift, a looong time ago. When I was a furre, or whatever.
Occasionally you might see me running around in a game as Xearius when Xion is already taken. No one better steal that name. I'mma be miffed if I see another Xearius running around.