There are many categories of military personnel maintained by the Masters throughout the Commonwealth, but all of them wear metal service collars which carry sliders. One of the functions of these sliders is to indicate rank.
The second diagram shows some of the work which culminated in the tables displayed in the first diagram. These tables show the ranks and insignia for the Ichorians, for legionaries and auxiliaries. Those displayed cover huimur (or dragon) crews and auxiliary or other aquar mounted forces. If you expand the image it will extend to cover legionary support staff.
The insignia are shown in two columns: the first for the Ichorian legion, the second for the other legions.
Note how insignia varies between the columns. This is a reflection of caste differences within the services. While the Ichorian double legion is recruited from the flesh tithe, all other legions have Masters from the Lesser Chosen as commanders; marumaga as the majority of the huimur crews and salt-paid, mercenary barbarians for the rest. The insignia thus reinforce racial caste differences. Among other things, it ensures that a Master can never be outranked by one of the Unchosen.
Insignia are based on Quyan numbers. Thus the sliders take the form of the broken or zero ring, , the ‘5’ bar [I], and a ‘spot’ rings [o]. The insignia thus code for a number. The higher the number, the higher the rank.
For example, a Legate’s four zero rings is the equivalent of 8000; a Righthand = 300; an aquar centurion for the Ichorians = 100; for a normal legion = 5.