The Thunderer was developed as a field conversion sometime during the 38th Millennium by a Departmento Munitorum field workshop as a replacement for lost Leman Russ Demolisher tanks. Using a Destroyer Tank Hunter chassis and a spare Demolisher Cannon, the field workshop was able to quickly replace lost Leman Russ Demolisher tanks. Due to the advanced technology used in the Destroyer Tank Hunters' Heavy Laser Destroyer being very difficult to repair and costly to manufacture, there are many unused Destroyer Tank Hunter chassis that can be retrofitted with a Demolisher Cannon. After stripping out the Laser Destroyer and its capacitors and batteries and installing the Demolisher Cannon there is only room for 18 rounds, and thus the tank cannot operate for long periods of time.