Thorac

Thorac was a Time Lord Cardinal. He was the leader of a schismatic faction of the College of Cardinals. He led his followers to Drornid and declared himself Lord President. On Gallifrey, he became known as the Heresiarch of Drornid.

On Drornid, Thorac erected a massive statue of himself, which towered over the local buildings. He established his court within the statue, and sent out a pacification beam from within it to control the local population.

The Time Lords dealt with the Heresiarch by completely ignoring him. Eventually, Thorac returned to Gallifrey, abandoning the people of Drornid, which collapsed into chaos when the pacification beam was turned off. (PROSE: Shada)

Behind the scenes
The rough outline of this story (the schism within the College of Cardinals and the rival Presidency on Drornid) is found in all versions of Shada, but the names "Thorac" and "Heresiarch of Drornid", as well as the details of Thorac's reign, are found only in the novelisation by Gareth Roberts.

A much darker perspective on the history of Drornid/Dronid can be found in Appendix I of the Faction Paradox guidebook .