Etoine

Etoine was a Zygon who was allowed to take human form after a ceasefire between humans and Zygons. He was forced to return to his true form by the leader of the rebel Zygon High Command, Bonnie, who shot a video of him running into the Fleet Estate Centre.

When the Twelfth Doctor and Petronella Osgood arrived at the shopping centre, they found two piles of dust, humans that Etoine had killed against his will. He was found by the pair, and the Doctor attempted to tell him that they could help. Etoine revealed that he just wanted to live as a human just like every other one on the planet. Desperately, he shocked himself, and was reduced to a pile of dust. (TV: The Zygon Inversion)

Behind the scenes
Etoine was not named on screen, only in the credits.