The Albino's species

From Memory Alpha, the free Star Trek reference

The Albino's species are a humanoid species with cranial ridges. (DS9: "Blood Oath")

Based on their appearance, it is possible that The Albino was actually a Klingon, although this is only speculation and given his apparent disdain for Klingons is unlikely. The script described him as "an all-white humanoid in good physical shape for a man of a hundred".