well, that spot is taken, but i guess we can think up some other word that basically means the same thing. but darkly stays as arch-nemesis (he tried to kill notchie, me pair). hmm, i can come up with "Bitter Rival" and "Sworn Enemy" at the moment.
name change for you? fine with me. .Silence is a tad annoying to type out, and i cant think of a decent nickname