Thijarian

The Thijarians were a species of assassins from their home planet Thijar. However during their assassinations, Thijar was destroyed. They were unable to grieve or honour those they lost, leading them to become witnesses across time and space, seeking to honour those who had died - or will die alone. They carried the remains of their planet and its people inside their hive.

The Thirteenth Doctor, Graham, Ryan, and Yaz encountered them whilst travelling to India in 1947, where the Thijarians were waiting to witness the many casualties from the Partition of India. The Doctor was not aware that their planet had been destroyed, or that they were no longer assassins. (TV: Demons of the Punjab)