Lady Carise Sindian is a Centrist senator and a member of the Elder Houses, created by Claudia Gray for Bloodline (Del Rey, 2016). She is the novel's engine of ruin: she discovers that Leia Organa is Darth Vader's daughter, manipulates Ransolm Casterfo into making it public, and then destroys him when he balks.
Her politics are a courtier's, not an ideologue's. She is aligned with the shadow organisation that becomes the First Order because that is where the future patronage is, and the ease with which she trades a functioning republic for a position in the next one is the point the book is making.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.