The Ethereal Bodyguard were conceived at the outset of the tau race forming to promote the greater good. On the tau homeworld after the intial bonding of the tau race, there remained some outlying settlements as stated in the codex, which did not take to the new utilitarian ethos immediatley. In order to incorporate these tribes into the race the ethereal caste had to travel across the homeworld of the tau spreading the message. The ethereal bodyguard were those amongst all of the caste whom embodied the ultimate philospohy of serving for the greater good, willing to give their lives in order to protect the ethereals so that they may continue to spread the message.
In the modern world of 40k the ethereal bodyguard continue to their role of protection the the ethereal caste, and it is considered to be a great honour to be chosen to join this tau unit as with the bodyguards of the battlefield commanders. The E,B protect ethereal buildings on all tau occupied world's and accompany the the ethereal caste's ships as they travel between them. They also fulfill the ceremonial guard duties, at bonding ceremonies.

I am going for a regal sort of look with my tau army, vermin brown and midnight blue on the armour. Skull white drybrushed with bleached bone will be on all of the commanders helmets.

any ideas for the selection process of joinging the ethereal bodyguard?