55th century

Tzim-Sha lived on the planet Ranskoor Av Kolos from 2018 to the mid 55th century. In this year, aided by the Ux, he planned to destroy Earth. He was stopped by the Thirteenth Doctor. Ryan Sinclair and Graham O'Brien when they imprisoned him in a Stenza stasis chamber in suspended animation. The Ux then sealed the building.

According to the Thirteenth Doctor, the years between 5418 and 5425 must have dragged on for Tzim-Sha. (TV: The Battle of Ranskoor Av Kolos)