The Imperial Sovereign, always a member of the Shi'ar race, is the ruling monarch and chief executive of the New Shi'ar Imperium.  Normally, the Sovereign serves for life, but may be removed by a two-thirds vote of the Imperial Council.  Succession to the position of Imperial Sovereign is semi-hereditary, as by the laws of the Imperium the Imperial Council must elect a new Sovereign from the ranks of the old Sovereign's relatives and family members. 

The Sovereign is technically the chief executive of the Imperium, but he or she normally appoints advisors and ministers to oversee the day-to-day functions of government. 

He or she is also supreme commander of the Imperial Guard

The Imperial Sovereign cannot initiate legislation, but the granting of Imperial Assent is required for bills passed by the Imperial Council and the Assembly of Alien Races before they become law.

Before the creation of the interplanetary New Shi'ar Imperium in Year 1001 (New Shi'ar Calendar), the Imperial Sovereigns were mainly the planetary rulers of Chandilar