Reconnaissance Dalek

A recon scout Dalek was sent to Earth in the 9th century, to gather data in advance of an invasion. Defeated by humans, the trisected Dalek mutant was buried in three parts, and came to be revived in the 21st century.

Arrival on Earth
Arriving on Earth in the 9th century, the Dalek was faced in the Battle of Hope Valley by an army made up of humans who had previously been at war with each other. Despite suffering tremendous losses, the army managed to "only just" defeat the Dalek, trapping it in netting and burning its casing. Practising caution, the Three Custodians split the Kaled mutant into three parts, each taken to different parts of the planet, and guarded by their descendants, so it might not recover. However, the third Custodian was shot by an arrow in Yorkshire, before he could complete his journey. (TV: Resolution)



Restoration
Buried by the passage of time, the Lost Custodian was eventually found beneath Sheffield Town Hall and the location became an archeological dig. On New Year's Day 2019, the Lost Custodian's piece of the Kaled mutant was found by archeologists Lin and Mitch.

The third piece of the Kaled was accidentally revived under ultraviolet light, and summoned its other parts. The Dalek subsequently took control of Lin, one of the archaeologists, and used her to gain intelligence, acquire transport, and retrieve its old gunstick. Using remnants of its old shell, combined with spare parts found at Dinkle's farm, Lin built this Dalek a new metal casing.

Letting Lin go, the Dalek went on a rampage. It killed an entire army detachment, and fired a missile into their tank, destroying it. The Dalek was intent on contacting its fleet, and made its way to the Government Communications Headquarters in order to enact its plan. It shut down all power in the UK in the process.

The Dalek was finally stopped by the Thirteenth Doctor, Graham O'Brien, Yasmin Khan, Ryan Sinclair, Mitch, Lin and Aaron using a microwave oven which melted its new casing. However, the Kaled latched onto Aaron, and demanded transport in the Doctor's TARDIS. The Dalek was finally thwarted when the Thirteenth Doctor jettisoned it into a supernova. The Dalek attempted to take Aaron with it, but Ryan managed to reach his father who fought off the Dalek's control while his son pulled him to safety. (TV: Resolution)

Behind the scenes
According to Darren Fereday, the concept artist, the Dalek was fully robotic and thus radio-operated, requiring no Dalek operator inside the casing. Three separate systems controlled the eyestalk, the gunstick and manipulator arm, and the lights. He also noted that the melted Dalek made use of practical LED lighting.