The Wise Man
The Wise Man is the advisor to the Dark Moon for most of the series and is the driving force behind the whole idea of destroying Earth. He's there pretty much from the beginning, offering advice to people on what to do to destroy the world. He has no problem with offing people if he feels they have outlived their usefulness or if they've found out too much about him. But besides all that, the Wise Man is also very mysterious, always hiding his face under that hood thingy. This can actually be kind of scary, as all you can see are those glowing eyes. He's not around very much either, which means that no one really ever knows what he's up to. His strange behavior gets the attention of one family member, who is promptly offed before he can do anything about it. But anyway......
Apparently in the anime, it seems as though the Wise Man's always been living out on Nemesis. He manages to hook up with the banished Dark Mooners sometime after they establish a civilization. He preys on their feelings of resentment and anger at being sent away from the Earth and is thus able to work his own agenda into theirs, which is to silence the universe in the name of some Doom Phantom. In order to do so he must wipe out all life. He uses the Moon Clan as his lever to get to Earth to destroy it and once he's there, he begins to kill them one by one, either because he doesn't need them or because they figure out too much regarding his motive. Pretty soon it's just him and the Wicked Lady, who is to open the Dark Gate and channel the energy to destroy the world (and herself). Sailor Moon shows up and turns Wicked Lady back into Rini, at which point the Wise Man reveals himself to be none other than the Doom Phantom (ta-da!). He says he'll do it anyway, but Rini and SM totally put him away.
The manga has TWM as what's left of an evil dictator who was kicked off of Earth and sent to Nemesis long before the Dark Moon Clan ever got there. Apparently, the first time Crystal Tokyo was established, a 'Mad Dictator Phantom' with big psychic powers got a hold of it and ruined the peace and tranquility. The Neo-Queen got to the bottom of it, however, and kicked him off the planet. He went to Nemesis, gave up his body, and melded his will with the planet itself. The planet then became his true form. (What is seen in the cloak is what's left of his original body.) He then lured the rest of the Dark Moon Clan out there with promises of power.
TWM also had a flashy pad known as 'The Wise Man's Castle of Darkness', located in the center of Nemesis. I think it was also located at the end of the 4th dimension, which means that the center of the planet is the end of the 4th dimension. Doesn't take a lot to put that together now, does it? That's probably why the end of the 4th dimension is forbidden. Anyway, Sailor Moon ends up destroying the planet somewhere near the end, killing TWM, obviously, because he is the planet.
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