A Dalek Observation Squad operated in secret on Tharius during the Last Great Time War. Their mission was to study the population ahead of them being harvested to become cyborgs to serve the Dalek cause.
The squad came out of hiding to attempt to capture Time Lords who had landed on Tharius, managing to capture Veklin and the incomplete berserker cyborg Case. They interrogated Veklin and managed to turn Case back to the Dalek cause, as her conditioning had failed, though in the process she damaged their base enabling Veklin to flee. With Case at their side, the squad followed Veklin to the artron generator which the War Doctor had setup to freeze a Dalek harvester about to crash on the planet and attempted to stop him deactivating it so the population could still be harvested. However Case overcame their conditioning with the Doctor’s aid and destroyed the Daleks. (AUDIO: Destroyer)