Skaldak

Skaldak was an Ice Warrior who held the rank of Grand Marshall. The Eleventh Doctor referred to him as "sovereign of the Tharseesian Caste" and "Vanquisher of the Phobos Heresy", and said "His foes honored him so much they carved his name into their flesh just before they died."

He commanded a fleet called the Nix-Thassis, with his daughter beside him.

For an unknown reason, he wound up frozen in the ice at the Earth's North Pole for approximately 5000 years, before being found by a Soviet scientist, Professor Grisenko, in 1983.

Impatient enough to wait until returning to Moscow, he was thawed by a crew member of the submarine Grisenko was serving aboard. Disoriented from the sudden awakening, he went on a brief rampage that sent the submarine to the bottom of the ocean. After an encounter with the Doctor and the submarine's crew during which he was knocked out and captured, he learned of how long he spent in the ice, sending him into a state of grief. This was exacerbated when he attempted to contact his fellow Ice Warriors, but they didn't respond.

Feeling he had nothing left to lose, he left his armour to learn more about the submarine and the humans. As soon as he learned about the nuclear missiles on board, he decided to fire them and wipe out humanity as payback for attacking him.

However, just as he was about to fire them, another encounter with the Doctor made him hesitate, and his companion Clara appealed to the memory of his daughter to make him stop.

He was shortly rescued by a martian ship, and deactivated the warheads as a final show of mercy before he left Earth. (TV: Cold War)