Warlord Broton was a Zygon commander and leader of the Zygon ship that crash-landed in the Devil's Punchbowl in Scotland in the 12th century. He kidnapped and took the form of the Duke of Forgill in Scotland in the lead-up to the World Energy Conference. While at the conference, he was shot and killed by the Brigadier. (TV: Terror of the Zygons)
Other references
In the video game Happy Deathday, played by Izzy Sinclair on the Time-Space Visualiser, Broton was among a host of "every single enemy" that the Doctor had ever defeated, who were assembled by the Beige Guardian and pitted against the Doctor's first eight incarnations. (COMIC: Happy Deathday)