Jean Mayeur
From Tardis Wiki, the free Doctor Who reference
Jean Mayeur was a 19th century French politician. He was also the Grandmaster of the Brotherhood of the Immanent Flesh in the late 1890s.
Montague believed Mayeur was trying to kill him, so he killed Mayeur to prevent that. However, Mayeur was able to survive by transferring his mind into Brother Tomas. He used the Quoth to overlay his personality on other politicians to increase his influence.
After Montague discovered his body-swapping trick, he killed Mayeur's other potential hosts. Mayeur was finally forced to transfer into his last host, Pierre Duval, where he was incapacitated by Roz Forrester and the Seventh Doctor. (PROSE: The Death of Art)
