Flying Dutchman

The Flying Dutchman was a individual whose identity the Doctor had always wanted to know. The Fourth Doctor asked Leela if she had heard of him, but she hadn't. (TV: Underworld)

The Doctor created an electronic avatar called the Flying Dutchman, who contacted FLORANCE and BAR B in the 30th century to obtain a list of mental patients with a specific type of pathology. (PROSE: So Vile a Sin)

Behind the scenes
In reality, the Flying Dutchman is the name of a ship from legend. The Doctor in no way makes it clear who or what the Dutchman is.