A very small, snow-pale viper native to Rshan. It is the only venomous creature of the North.

Wordlessly, Nenos held the box out to Liall. The prince took it and jerked the cover off. Inside, nestled on a bed of folded red silk, was a white essima, the tiny, fanged, ruby-eyed viper of the north that ever seeks warmth, hiding under pillows and cushions and near warm chairs. So silent it was, and so swiftly did it kill, that the name for this snow-pale serpent and the name for assassin are the same in Sinha.

-Scarlet and the White Wolf: the Land of Night, page 133