DarkHououmon is the name of a female digimon antagonist from an ancient, unfinished, and awful Mary-Sue Digimon fanfic I wrote many years ago. I liked Hououmon, and I liked the viral versions of Digimon, so I just made one out of Hououmon, thus DarkHououmon. This was before I knew of the english name, Phoenixmon.
Nowadays, I no longer use the character of DarkHououmon, and instead use the name strictly as a username.