Deon

The Deons were a religious group on Tigella. They worshipped Ti and held the Dodecahedron to be a god-given gift.

Opposition
The Deons opposed the Savants and their scientific methods. Meglos stole the Dodecahedron in the guise of the Fourth Doctor. Lexa, leader of the Deons, ordered his arrest. Zastor granted the real Doctor access to power room.

Revolution
Lexa did not believe the Doctor's story about someone taking his appearance and so she ordered a revolution. The Deons rose up and arrested the Savants. As non-believers they were sentenced to the surface. This was also Zastor's sentence. Lexa told him that his faith was but words without action. Lexa hoped that sacrificing the Doctor would return the Dodecahedron and so they captured him and instigated a ceremony of his death.

Aftermath
His sacrifice was prevented and the Doctor was proved innocent. However, Lexa was killed by a Gaztak. The Dodecahedron was taken to Zolfa-Thura where it was lost. (DW: Meglos)