Po Nassi was one of the creaters of the Cloral poison fertilizer along with Ty Manoo. Po Nassi is actually Saint Dane in disguise. The fertilizer was supposed to make plants grow fast, but Saint Dane tampered with it and made it poisonous.
Bobby describes Nassi as tall and slim and she has sharp feature that reminded Bobby as a sly cat. Po Nassi appears in The Lost City of Faar.