The high concept and trouble do a lot to define who your character is; it's not really possible to make suggestions for them without knowing what kind of person they're for.
Who is this seneschal? What drives them? What do they do all day, other than Kringle's bidding? What are their flaws, and what problems do they have in life?
This. Also, what sorts of relationships do they have? Do they associate with Kringle and Kringle alone always and forever?