At present, very little is known for sure about what qualified an individual Chiss to become an Aristocra, and the range of powers vested in the rank are likewise unclear - problems that are partially due to the fact that only two Chiss of this rank seem to be known from extant sources: Chaf'orm'bintrano and Mitt'swe'kleoni, with Chaf'orm'bintrano being the rather better recorded of the two.
Chaf'orm'bintrano was a representative of the Chaf Family apparently representing a pure-blooded cadet lineage within the kindred, and in this he can be contrasted with Thrawn and Thrass, Syndics of the Mitth Family, who had been born commoners and adopted into the affinity due to their abilities. In the light of this, it is possible that the title of Aristocra was generally accorded to blood members of a Family, with Syndics being coopted by adoption - but this hypothesis is by no means proven on present evidence, and alternatives exist: for example, Aristocra and Syndic may have been titles denoting similar positions in different Ruling Families, or else the title may have denoted a simple rank or sphere of operation. While both known examples of an Aristocra were male, there is no direct evidence as to whether females could hold the same rank.
In most known encounters, an Aristocra was found serving as the head of a military or diplomatic expedition, but this may reflect the nature of outsiders' contacts with the Chiss rather than the general range of responsibilities of individuals of this rank. Perhaps more confidently, it could be observed that an Aristocra normally seemed to have served as a representative of their Family or even of the Ascendancy as a whole, charged with carrying out a specific mission and enjoying wide-ranging authority in the execution of the resulting duties.
From the rather sparse records, it can be said that an Aristocra might serve as an envoy in contacts with outsiders, as civilian leader of a military expedition, as the primary representative of his Family's interests in a particular volume of space, or as commander of a private military venture designed to strengthen his Family's stance against other power-blocs within the Ascendancy. On his own authority, an Aristocra could also arraign an officer of the Expansionary Fleet for trial and take him into his own custody - even in the face of objections from an Admiral of the Defense Hierarchy. An Aristocra also outranked generals.
As so often with information relating to the Chiss, it must be noted that part or all of what we think we know about the title of Aristocra may be misinformation or misunderstanding. There is even some doubt as to whether the Aristocra Chaf'orm'bintrano encountered by the crew of the Bargain Hunter in 27 BBY was indeed the same individual met in 22 ABY and later by Luke and Mara Jade Skywalker and other representatives of the New Republic and Galactic Alliance.