According to the in-game encyclopedia in Vandal Hearts: Flames of Judgment, Biruni is "A country to the northeast of Balastrade. Biruni is know for it's great mages and scientists, and also for its strict immigration policies; its borders admit only the brightest, or those willing to commit to strenuous labor."It appears that in this Ancient Empire, intellectual capacities are highly welcomed and praised, as they make a great effort to find foreign geniuses and instruct them via the Biruni University. One of the few ways to get into Biruni is to be accepted as a student there.
According to the in-game encyclopedia in Vandal Hearts: Flames of Judgment, "The Biruni network of universities extends outside their own borders, with branches in both Shumeria and Thane. These serve as both schoolds and embassies, and only students and staff are traditionally allowed inside - though there is the occasional exception-." The Ancient Biruni Empire and its capital, Braph, are still around during the events in Vandal Hearts: Flames of Judgment and are important places during those days; however, about 1000 years later, when the events in the first Vandal Hearts game take place, the whole nation of Biruni has dissapeared to the point that many believe such advanced empire was just a myth.
Along the games, it is easy to know which are Biruni ruins and artifacts even when it isn't directly stated, because all of them have the same Biruni symbol or picture of a giant flying creature with a cross on its chest which appears to be some kind of bird or phoenix-like animal, but that may as well be, as some fans hypothesize, the silhouette of the Salamander Dragon, guardian of the Torog area that lives in the Smoking Bones Cave and that can be summoned to perform an attack spell in all three games in the series. It is unknown how exactly this superior Empire dissapeared. For some reason, Biruni people seem to have exceptional magical and intellectual skills, and only those with the blood of their race are able to use or activate Biruni artifacts and ruins.
In the first Vandal Hearts game, there is still some Biruni people alive (though they deny being such) but, upon hearing of them, Sabina is sent to kill them all so that there is no Biruni left to help Ash and his party obtain the Vandal Heart sword; however, Lena, a little child from the village, survives (since she wasn't in the village at the time of the attack) and stays with Ash and the others to help them, but Xeno manages to send her through a hole in time in the last moment, before she can release Vandal Hearts, and apparently completely banishing the Biruni kind from the world. In the end, it happens that Eleni is the adult form of Lena after she was sent back in time by Xeno, so there is still one Biruni alive that it's known, and it was her to finally release Vandal Heart so Ash can fight the Flames of Judgment.