Deming Chen is a high ranking member of the Blue Blood community and is first introduced to us in the second novel Masquerade. Not much is known about Deming aside the fact that she is Kuan Yin the Angel of Mercy and has a twin sister Dehua Chen who is also Xi Wangmu The Angel of Immortality.
When she is reintroduced into the series in Misguided Angel, you get a more in depth look at her character and history. You find out that she is a Venator with an impressive resume and is brought to New York to find a kidnapped Blue Blood, Stuart Rhodes, and to stop a coup d'etat so that the New York coven will stay together.
It is soon seen that Deming is not your average Blue Blood as she also was allowed to become a venator early like Mimi and Jack. She is seen using many powers that are not common to Blue Bloods such as aura reading without using the glom and also taking part in a Death Walk which could have taken her out of cycle.
Paul is first introduced to the series as a possible suspect in the disappearance of a young blue blood. when Deming meets him she see's him as harmless and naive and she feels a grudging pull of attraction. Afterwards it is revealed that he knows about vampires. Deming believes she has truly fallen in love with him and performs caerimonia oscular (the sacred kiss). It is soon revealed to be a ploy as he soon shows himself Nephilim (half silver blood, half human) and he got her to perform the sacred kiss so she would not be able to harm him. this proved to be incorrect as he was only half human and was then killed by Deming.
Sam Lennox like Deming is a true born twin meaning that he and his twin were born of one star that was split in two and as such doesn't have a true bondmate.