Primus, was the highest modron and ruler of the modron civilization. It was godlike in power while in his realm.
Primus had near godlike power within the realm of Nirvana. Its power over the modrons was absolute. All modrons obeyed the orders of Primus and carried out its plans. It was entirely immune to magic, and could issue telepathic commands to all modrons on Nirvana.
Primus, although godlike, could be killed. Whenever slain, the highest-ranking secundus modron was promoted to his position and became the new Primus.