Friday (Empress of Mars)

"Friday" was the name given to an Ice Warrior who was abruptly awoken from hibernation. Discovering his homeworld had died, he undertook a search for his hibernating Queen.

An ancient war
On ancient Mars, Friday fought in a war and pledged allegiance to his Queen, Iraxxa. As a sentinel, it was Friday's role to guard the hive - a hive which was forced into hibernation. Friday slept in a cryogenic cell aboard his ship for around 5 millenniums.

Awakening from stasis
Friday's ship crashed to Earth in 1881, where he was discovered by Colonel Godsacre in the South African veldt. Godsacre named him "Friday", after Man Friday from Robinson Crusoe.

Friday was injured and in an comatose state following the crash which had left Friday's cryogenic cell damaged. He also needed help repairing his ship. Friday promised Godsacre and his men treasures in exchange for their help.

Returning to a dead planet
The ship crash landed on his return to Mars. Friday helped the soldiers build the Gargantua from part of his ships artillery. They believed that it was for mining gemstones, but Friday was using them in his search for Empress Iraxxa and the rest of his hive. As part of his deception, Friday dissembled and became a servant of the soldiers.

Some months later, Friday discovered the Twelfth Doctor in one of the caverns. He had travelled to Mars with Bill Potts.

The soldiers uncovered Iraxxa's chamber, where the Queen lay dormant in hibernation. As Iraxxa was awoken, Friday fulfilled his pledge to her. However, Iraxxa attacked the humans and awakened her hive to fight alongside her once more.

Choosing a side
Friday was forced to choose between his Queen and those who had helped him. He freed the Doctor, Bill and Godsacre from the brig. As Captain Catchlove attempted to make an escape by holding Iraxxa hostage, Godsacre shot him. Godsacre agreed to serve Iraxxa and remained on Mars with Friday and the rest of the Ice Warriors. With the help of Alpha Centauri, they would leave the dead planet Mars and begin a new life elsewhere in the universe, starting the Martian Golden Age. (TV: Empress of Mars)

Personality
Friday was, as an Ice Warrior, very loyal to Iraxxa, his queen, and followed the Martian code of honour. He was not above using deception and lies in order to get back to Mars, easily manipulating humans through their greed by promising them untold riches. However, this act was not out of malice or ill intention but loyalty and dedication to his race.

He stood out from other Ice Warriors in that, instead of blindly following his queen and slaughtering soldiers pointlessly, Friday desired peace and understood that there was no point in dwelling in the past. (TV: Empress of Mars)

Other
At some point the Twelfth Doctor, Bill Potts and Nardole saw a vision of him in a library. (TV: A Time For Heroes)