Sebastian would be a great character to pair with Pluto. Their master - servant relationship has a lot of potential for exploration. There's the power dynamic, with Sebastian being in control but Pluto having his own strength. It could lead to some interesting power struggles and character development.
I'm afraid I can't tell you the author of 'pluto the series novel'. However, if you search for it on platforms like Goodreads or Amazon, you may be able to find out who wrote it.
Since I don't know the exact 'Pluto Series Novel', I can't tell you the main characters. But usually, in a novel series, there are protagonists who drive the story forward. They could be ordinary people caught up in extraordinary situations related to the Pluto concept in the story.
Since it's about Pluto, Pluto is likely to be the main character. There may also be other characters like Santa Claus if the story involves the typical Christmas elements. Or it could have other animals or people in Pluto's world who interact with him during the Christmas story.
One could be a scientist who is obsessed with Pluto's mysteries and the other could be a being from Pluto itself. For example, a shape - shifting entity that the scientist discovers during his research.
A love story for Pluto might develop through shared experiences. For example, if there was a threat to the manor and Pluto and this potential love interest had to work together to protect it. During this time, Pluto could realize his deeper feelings for her. His loyalty to the manor and his newfound love could merge, making him even more determined to protect both.