Badger Berkeley

In the novel And Then There Were None, Badger Berkeley is a friend of Tony Marston.

Role in the novel (warning, it may contain spoilers about the plot)
The killer used Badger's name to lure Marston to Soldier Island. Badger had actually gone to Norway for an indefinite period of time, so Tony was surprised to receive a telegram from him.

Badger never appears in the novel.