Thijarian

The Thijarians used to be assassins from their home planet Thijar. However during their assassinations, Thijar was destroyed. They couldn't grieve or honor those they lost. They soon turned to become witnesses across space and time, seeking to honor those who have died - or will die alone. They carried the remains of the planet and it's people inside their hive.

The Thirteenth Doctor, Graham, Ryan, and Yaz encountered them whilst traveling to India in 1947. The Doctor did not know about their planet being destroyed. (TV: Demons of the Punjab)