During her tragic death scene, Pluto tells everyone of her wish to fight with them. In (approximately) act 28, she does. She appears with Uranus and Neptune and destroys Tellu with Dead Scream. It is she who tells the Princess and the Inner Senshi of the Outers' mission, past and present.
In SuperS, it appears that the Outer Senshi have lost their ability to transform. They think that their mission is over and give their all to raising Hotaru. However, after Hotaru grows up and gives them their Sailor Crystals, they go to their prince and princess to help save the day.
With the power of Charon Castle, Pluto helps Usagi become Eternal Sailormoon and powers herself up to Eternal Sailor Pluto/Sailor Star Pluto. Unfortunately, she is soon after taken by Galaxia in that castle and is under Galaxia's control.
The bond between Pluto and Small Lady is that of a lonely, affectionate woman who wants to have someone to love and a lonely, emotional child who desperately wants to be loved. Pluto is there to bestow kisses and hugs when Neo Queen Serenity cannot be there. She says that the reason she loves Small Lady so much is that she's so honest.
On the subject of Endymion and Pluto, there is only one real thing that needs to be said: it never came into the story, so it doesn't matter.
Pluto's first fuku is black and/or deep purple with deep red (the bow) and magenta (her earrings and the token that hangs from her choker). Like Mercury's, it has no sleeves, and they wear the same boots. Like Uranus' and Neptune's, however, Pluto's gloves stop about halfway up her forearms. Sailor Star/Eternal Sailor Pluto becomes slightly more violet, with the pale lavender skirt under the dark one. Although Saturn has domain over purple, hers is brighter with more red, while Pluto's is dark and more blue.
