David Roche was an early 1700s soldier, officer, vicious duelist, and adventurer. A middle-class Irish gentleman by birth and education, he was hailed as a hero and damned as a thief and possibly a murderer at various times in his life. He gained his nickname when he sank his teeth into the throat of a rival during a fight. Nothing is known of his later life, but did Timewatch recruit him? Did he somehow gain access to time travel to bedevil the corridors of time? Is he simply someone who makes life more difficult for time travellers he meets?
David "Tiger" Roche on Wikipedia