Tau Commander
Tau Commanders are often captains or leaders of a Tau army. Sometimes they replace a Ethereal as authority force if they aren't present. Usually Commanders go to battle in a Crisis Battlesuit. Tau Commanders differ in doctrine depending on their Sept of origin. Commanders hailing from Vior'la, Tash'var, and Kel'shan are noted for their personal kills while those from Elsy'eir and T'olku are known to be more cerebral in nature.
Shas'el
Shas'el is the second highest rank which a Tau Fire Warrior can attain. A Shas'el usually only gains the rank after years of training and battle experience. A Shas'el will usually command smaller engagements of small Cadres leaving full Cadre and multi-Cadre actions to a full Shas'o.
Shas'o
A Shas'o is the highest rank in the Tau army which a Fire Warrior can attain. Becoming a Shas'o means going through several Trials By Fire and progressing up the ranks from Shas'la to Shas'ui to Shas'vre, then becoming a member of another commander's bodyguard, to Shas'el and then finally to Shas'o. After becoming a Shas'o, the only remaining options are to either teach at an academy, become a military advisor to the Shas'ar'tol or join in politics and be on one of the many councils in the Tau Empire. Besides death, this is the only way a member of the Fire Caste can leave the Tau military.
Some Shas'o wear armour with inverted colour schemes. For instance, O'Shaserra and O'Kais both wore white armour with sept markings picked out in yellow, the reverse of the regular T'au Sept's colour scheme. O'Shovah is another example of this, as is Or'Es'Ka Whether this is the norm for Shas'o is unknown.