Vagra II was the formerly inhabited second planet of its star system. The planet was located in the Zed Lapis sector. Prior to 2364, little information on the planet was kept in the library computer, other than the fact of its existence. Sensors indicated no signs of lifeforms, virtually no vegetation, and the minimum atmosphere requirements for humanoids.
A "race of Titans" once brought out from within themselves all evil and negative attributes that had bound them to destructiveness. As a by-product of this procedure, the unwanted substance spread and coalesced into a dank and vile second skin, Armus, a "skin of evil". The race rejected this malevolent sentient substance and abandoned it on Vagra II.
In 2364, Armus threatened the crew of a USS Enterprise-D shuttlecraft that had crash landed on the surface. It also killed Lieutenant Natasha Yar, who was part of the away team assigned to recover them. After the crew of the Enterprise-D escaped, they destroyed the shuttle wreckage to trap Armus on the planet. Vagra II was subsequently placed under quarantine. (TNG: "Skin of Evil")
According to Star Trek Encyclopedia (4th ed., vol. 2, p. 448), the species that created Armus was native to Vagra II.