Kiron

 was the son of Lambert.

When Lambert saved the Twelfth Doctor's life from robots in the Forbidden Zone, he and Kiron refused to leave in the TARDIS, as it was still their home. Instead, as a thank you to Lambert for saving the Doctor's life, the Doctor promised to protect Kiron. He did this by installing a low-level telepathic link in Kiron's wrist device. Each time the Doctor protected Kiron, he had Gladvis film him. Soon afterwards, the clips went viral and Kiron grew in power, eventually becoming President.

After examining the device, Kiron was able to amplify its telepathic link and he controlled the whole planet's population. He made them restore the city and enslave the people's enemies, and Kiron could do whatever he wished. When the Doctor discovered this many years after he first met Kiron, he promised to stop him. He withdrew his protection of Kiron, breaking the spell on the planet's people. Realising he had done wrong, Kiron asked the Doctor to help set things right. (COMIC: The Promise)