Sure, he's merciless, and tortures his fellow Seishi as well as his enemies, but does he have a Pipe Organ? 

He does now! 

Every self respecting villian needs a top hat. How's a man supposed to concoct nasty schemes when his head is cold? If you're gonna rule with an iron fist, you gotta do it with some style, so now Nakago is looking good. 

Optional extras for ruling the world include a monocle, a black cape, and a pencil thin, diabolical moustache. 

Well! That's much better! Now Nakago can tie Miaka to the railroad tracks while muttering "Fools, Fools, I'll destroy them all!" 

Wait a minute, there's no trains in the "Four Gods" book... 

Curses! Foiled again!