Ars Dangor is a human Imperial adviser, recognisable by braided moustaches and an assortment of wide-brimmed hats, who appears among the Emperor's entourage in Return of the Jedi (1983) and was folded into current canon through James Luceno's Tarkin (2014). In Legends the character originated earlier still, in "Imperial Spin" in West End Games' Imperial Sourcebook (1989).
He served as a Senior Advisor to Supreme Chancellor Palpatine during the Clone Wars and joined the Imperial Ruling Council under the Empire. In 5 BBY his part in closing the shipping lanes to Ghorman — with Sly Moore — put him at odds with his wife, Mon Mothma, which is a marriage the current canon has quietly made one of the more interesting footnotes in the Senate.
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.