Pa Nguyen was a Vietnamese man, the verbally abusive father of Diane Nguyen and the head of the Nguyen family. In his daughter Diane's words he was a "mean, sadistic alcoholic who never supported anything she did and actively delighted on seeing her fail." Nobody in his family seemed particularly grieved by his loss and just wanted his body out of the family home.
He died in his sleep in 2014. His sons made the discovery after playing a prank of doodling his face before they realized he was dead. As a result, his body is left to rot for hours.
Diane organizes what turns out to be a pointless funeral as her mother and brothers had his body chummed to be thrown at Derek Jeter (much to Diane's shock and horror) who was Pa's alleged rival though it is doubtful Derek Jeter was aware of Pa's existence (therefore, an entirely one-sided rivalry). In his chummed state he rolls towards Derek Jeter who is aiding an old lady cross the street practically knocking them over. The container is then lost somewhere in Boston.
- Like his wife, his real first name are never revealed.
- He and his wife are similar to Butterscotch and Beatrice in that they are verbally abusive toward their children.
- There is a flashback in a previous episode where he is shown alive.
- Despite the abuse he gave Diane, she lied to BoJack to get him to open up while writing their book, she claimed she sat on the roof and look at the stars with her father.