Denonn was a Top Gun-calibre flight instructor from the Minbari Warrior Caste. The MUX was still fairly new and sparsely populated when I was playing there, so I spent most of my time building parts of Minbar. Unfortunately, the makers of the game spread out too many RP areas so unless you had a concept based on the Babylon station, you really saw little RP. I think I played all of one scene before I left.
Babylon 5 was the only one that I ever left on bad terms. The head of the Centauri faction at the time was an incredibly rude jerk over a channel transgression that I made and was entirely belligerent in the process of resolution. Given the choice, even if the MUX is now the best Babylon 5 MU* around, I would not log onto the site ever again.