You might remember that Deb used to be human at one point but was turned into a sorquine (which saved her life.)

A sorquine's level of intelligence depends on their original species. They don't lose any of their memories (unlike, say, the Kobali from Voyager.)

Sorquines are native to a star system in the Klingon Empire. They say no Klingon dares go there for fear of being robbed of an honorable death.