David Ferraro

 was the first officer on the Constitution III when they took Marshal Grover's expedition to the island of Salutua in 1934. Nancy Norton convinced him to take the huge ruby from the giant statue that was found there. However, the statue was Brokk, a Grold rendered immobile by the relative cold on Earth. Brokk hypnotised David and made him build a fire to warm him up so he could move again. Because the Third Doctor created a time bridge to the island from UNIT in the future, several potential timelines were created. (PROSE: The Eye of the Giant)

Original timeline
He died with the expedition when the volcano on the island erupted after Brokk's ship crashed into it.

Alternate timeline 1
He was one of the first people who Nancy implanted with Brokk's eyebrain fragments, converting him into a minion. He helped Nancy take over the expedition's crew after leaving the island, then aided in her campaign to control the world.

Alternate timeline 2
He was killed when the Third Doctor used his sonic screwdriver to shatter the eyebrain fragments.