Dragon King of Arms is a vampiric heraldic creator. Prior to his library being destroyed in a freak accident, he had extensive records on many of Ankh-Morpork's noble families. With heraldry and coats of arms becoming fashionable, he has been catering to customers of less noble lineage, such as bakers and candlestick makers.
He has a great linguistic mind, and many of the heralds he create contains puns or jokes, such as the motto for the president of the Baker's Guild being QUOD SUBIGO FARINAM (I Knead the Dough).
He was also the mastermind to remove Havelock Vetinari from power and make room for a new king. However, he feared the possibility that, due to true heir Carrot Ironfoundersson's relationship with Angua, that the future king might be called Rex. He claimed that he had tracked down the descendent of Duke de Nobbes, Cecil Nobbs, much to Commander Vimes' surprise.