The Nra is the standard currency used by the Galactic Senate.
For much of the Milky Way's spacefaring history, nations have been separated by a wide array of factors, including differences in currency. Many small alliances of nations attempted to form standardised currencies, and some even succeeded. None of these currencies ever gained much influence on the galactic stage, and over time, were phased out due to economic troubles and their disastrous effects on the economies of all participating races.
Early in its existence, the Galactic Senate intended to tackle the issue of different currencies by issuing its own money. Keen to the failures of past attempts by other groups, the Karnasaurs led the charge in forming a stable currency that would not fluctuate wildly at the whims of economically troubled factions. Thus, the Nra was created, and is printed and coined even thousands of years after its conception. While it remains a forefront monetary unit, currencies like the Eteno Grum are becoming more and more common in once Nra-dominated areas of the galaxy. It is even said that some in the EIT may be even trying to sabotage the Nra to the benefit of the Eteno economy and cause a galactic inflation crisis. The scariest part of this rumour is that it's not too far from the truth.
Keen to the failures of other unified currency attempts, the Karnasaurs put forth the idea that not all Nra users would use the currency at all times. If a race that used the Nra ever went into economic crisis, the unit would be removed from circulation, to be replaced by a local currency, bartering, or a prepared 'emergency unit'. That allows the Nra to not decline in value in the face of economic collapse of one of its users, but still benefit from economic growth of other users.
It was also agreed that the Nra would follow a standard, a bread basket of gold, diamond, platinum, and other precious metals. This is one of the currency's prime shields against the devastating force of inflation.