mmmmmmmmm... quick removal of internal organs.... grallochin' bastiges rocks...
the Kerambit's big cousin, The Civilian, can eviscerate a Mumakil...
It still only counts as one...
Eyes are also a good target for reverse-curve blades like that.
The traditional karambit is a fixed-blade knife, double-edged, and has to be carried in a sheath. That ring on the bottom is the key to its deployment, and either the index or pinkie finger can go there, depending on the moves you want to make.
The karambit is most definitely a martial-arts item, and requires practice to do more than the basic slash/eviscerate. I have a blunt all-aluminum practice karambit that doesn't do any damage to me, except getting whacked on the wrist a little hard when I really spin it. It has potential as a non-lethal weapon that can do things that even a nightstick can't, like using the blunt hook-end to convince someone to get out of a car seat.
Another nice feature of the Spyderco folding Karmbit is that it has nice pointy areas on both ends when the blade is closed. Helpful for pressure points, or just to punch someone in a vulnerable area with.