Leading contenders are, IIRC, Captain Chaos (Which I always pronounce in the old 'Captain Caveman' voice), Alice (Alice Haeffner), one of the known AIs, Pyramid Watcher, or ... crud. SOmeone whose name I just blanked on. Grid Reaper? No...
Ackl.
At any rate, I have a guess (Not a theory, mind, just a guess!) which 've passed on, but won't chat about in case I'm right.
I will go ahead, however, and ask who the crowd would rate as the top, say, ten known Deckers.