The Valzhans are a humanoid species native to a planet with the same name in either the Alpha or Beta Quadrant. The majority of the Valzhan race has amber skin, emerald green eyes, and long blond hair which turned gray during old age. Instead of a Human like nose, they have a set of four small holes centered beneath the eyes. (SCE eBook: Where Time Stands Still)
Initially Valzhan was reluctant to join the Federation because of their strong convictions against violence and also because the Valzhan wishes that they retain their privacy. Due to the significance that its star system's lie within a close proximity to the Klingon border, the Federation spent a great deal of diplomatic effort - which lasted over a century - to secure Valzhan as an ally. Because of this, the Federation is sensitive in their support of the Valzhan race to retain their privacy and that is also why Starfleet data banks hold only scarce information on the planet.
What is known is that their civilization at one time had been quite advanced, having attained interplanetary travel capabilities until global war ravaged their planet, interrupting their advancement toward the stars. The Valzhan survivors then shifted their priorities to that of simple survival and concentrated their efforts on rebuilding Valzhan, which took many centuries to complete. Presumably they had completed their rebuilding efforts and shifted their attention back to space travel sometime before 2258 and 2268. It was within this decade they had developed faster than light travel and it was during this time they encountered Starfleets' first contact team. (SCE eBook: Where Time Stands Still)