The Necrons have a very rigid feudal hierarchy dating back to the time when they were still Necrontyr, and it was made part of their most basic programming when they were upgraded into Necrons.

Whereas Necron lords only rule over a single Tomb World, a Necron Overlord may hold anywhere from 3 to a dozen Tomb Worlds in his sway. And as the Lords bow in service to their overlords, the Overlords of a Necron Dynasty kneel to the Phaeron, the SPACE EGYPTIAN ROBOT ZOMBIE KING OF KINGS for his word is law, more so now since there is no Triarch council to keep the different dynasties all on the same page.

Necron Overlords have a closely kept circle of advisors and viziers, consisting of high-ranking Crypteks and lesser Necron Lords.

This 'Royal Court' of knowledge and influence not only help the overlord fight on the field of honour, but also serve as his eyes and ears among the dissenting nobility beneath him, assuming there is any, or assuming that his courtiers aren't in on the coup.