Setsuna Meioh is probably one of the most mysterious characters. There are slight clues to her past but we really don't know much about her. We do know that she's the daughter of the God, Chronos. We also know that it's forbidden to know that she exists.
Setsuna specializes in astronomy and things having to do with time. She also is a little more psychic than Raye due to her Planet Power. Setsuna, like Lita is very motherly. StarS 1 introduces her as the school nurse and Hotaru's mother. Like Amy, she is very good with computers and even helps Amy create new computer programs to detect the enemy (GN #10 - #13). Setsuna also holds a slight grudge against the inner senshi left over from the days of the Silver Millenium but ignores it most of the time knowing that the past is the past and the present is now.
Sailor Pluto has to be the third deadliest of the scouts. Her attack Dead Scream can rip appart anything and almost killed Sailor Moon in GN #5. Her weapon of choice is the Garnet Sceptre and the Garnet Orb. The Garnet orb is one of the three talismans that wakes Sailor Saturn and hails the destruction of earth. Her attacks have to do mainly with time and death. Kinda morbid, ain't it? As previously stated, she holds a slight grudge against the inner senshi from the days of the Silver Millenium. Pluto, like Uranus and Neptune, stayed on their home planets and defeated incomming enemies. This was a hard job, very lonely, and very brutal. She feels that she could have had more use with the Inner Senshi. She knows though, that the past has gone and she must live in the present.
Setsuna enjoys the peaceful times, like when she was raising Hotaru in the SuperS or right before Galaxia invaded in the StarS. She knows that her mission, along with the other scouts is to defend their home and protect the princess. She doesn't argue with this and actually takes her mission with pride.