The Xi’an ( kyexiin: rĩ@Xà’N(Proper); SRX: Xy’an (Proper) Jh’an (Service); ) are a sentient, ancient species of bipedals. They are a calculating and peaceful alien race that is at peace with Humanity.
Not much is known about the history of the Xi’An yet. It is known that they once lived on a lush, tropical home world named RyiX'yan and that they were not always at the top of the food chain. At some point in time they abandoned their home world. 
Their history is marked by various conflicts - internal and external. The end of the last tumultuous period around 2500 Earth years ago, resulted in the so-called Third Age and ascension of the still ruling family of current Emperor Kr.e.
In the darker era of human history, the Imperator and government often used the Xi’an threat as a means to terrify their own citizens and swell the power of the military. Although neither side declared open war, there were many casualties due to the covert operations that both the Xi'an and Humanity took part in.
The Xi’an Empire located along the border of the Eastern Systems is comprised of at least fourteen systems. The Xi’an government has not disclosed the exact number of systems under their control but it is assumed that they have more territory deeper into space.
The Xi’an Empire is a hereditary absolute monarchy. The title of Emperor passes down through the family line. The emperor has a High Council of Advisers, each representing a facet of the government.
On each planet under Xi’An control there is a similarly structured Council that runs that world. Those Council Members report directly to their respective counterpart on the Emperor's Council.
Due to their extended lifespan, there are Xi’an from hundreds of years ago that are still alive. For example, Emperor Kray who negotiated the daring peace accord with Senator Akari back in 2789 is still alive and in power.
There are undoubtedly members of the Xi’an government who still regard the UEE with suspicion and distrust. The current Imperator has always been clear that our futures are intertwined. As more human corporations enter into tech-exchange deals with Xi’an companies, apparently they feel the same.
Military service is compulsory. Every male and female is obligated to serve a term of service (fifteen years) in one of the branches of the military and are considered to be reserve members for the rest of their life. Estimates place the standing Xi’an armed forces at over sixteen million. This is not including the civilian populace, all of which have some form of combat training.
As far as the UEE has had established contact with the Xi’an, they have not been the aggressors in any wars that we know of. Based on information supplemented to the Ark, their history is rife with civil war and power struggles. Over the past five centuries, the Xi’an have adopted alternate methods to warfare, they prefer subtlety and manipulation to overt conflict. Analysts have concluded that it was through Xi’an influence that the revolution and subsequent overthrow of Imperator Messer XI was able to succeed back in 2792.
Helpful Phrases (presented phonetically)
Shē'sueren – translated "Hello and greetings with peace." This is a formal greeting and is only to be used among close friends or with trusted business partners. Use of this phrase in a casual manner or when approaching a situation with tension or duplicity will immediately marginalize you in the Xi’an's eyes. One could argue that it's a pledge of truth and honor as much as a greeting.
Chac – A casual hello. To be used among peers or to subordinates. Use of this phrase from a subordinate to a superior or to a Xi’an of a higher caste than you will cause offense.
Athlē-korr – "Safe Travel" a formal good-bye. Roughly the equivalent of Godspeed in ancient Earthen sea-faring days.
Gath – Casual good-bye.
It seems like their language is very socially constructed and tonal? What happens if I do make an error?
A majority of the Xi’An can be quite forgiving when it comes to minor social infractions. They understand that, more often than not, it is not intentional and appreciate the effort to learn their customs. But if you find yourself offending a Xi’An, you don’t have to worry. They won’t get angry or try to kill you. The Xi’An find such displays of emotion to be immature. They will simply shut down and become curt, succinct, and intractable
Most of these social rules only apply to the first several meetings. Once a bond of trust or friendship is established, the Xi’An are quite forthcoming and relaxed.
"The true value of a moment is learned upon its story being shared."
–Traditional Xi’An proverb