Sailor Saturn is the Senshi of death and Rebirth. In Roman Mythology, Saturn was God of the Harvest. This was directly linked to life in ancient Rome, and the harvest grew again, reborn every spring and summer. Saturn would of course influence it's satelite. This is where Pandora gets her powers in part.
In Greek and Roman Mythology, there was a woman named Pandora. This woman was not born, but sculpted to be beautiful and perfect in every way. Into her keeping was placed a box that held all the plagues of humanity. She was merely instructed not to open the box, and sent on her way.
Curiosity as to what was in the box ate at the woman until she just HAD to open it. (Adam and eve Roman style!) And when she did so, all the plagues escaped. (i.e.lust, hatred, jealousy, spite) Lucky for her, she slapped the box shut before the weak hope escaped, because if it had, all the stronger emotions would crush it and humanity would be doomed, for without hope, life is colorless.
Tskui's powers definitely have their dark side. In a way you can understand why she is the solitary senshi.