Neppers are bipedal creatures that, although they are animal, have a very plant-like appearance. Their bodies appear to be stems, and their limbs look oddly like leaves. This was most likely evolved to aid in camouflage and thus help neppers ambush prey.
Neppers are a very varied folk, speaking in terms of personality. Some of them are very wise and kind, while others are nothing but sadistic thugs. However, there's one unifying factor- they all love to eat rees.
Neppers originated and evolved on the planet Lusitania.
Lusitania was, at one point, attempted to be colonized by the rees. The Neppers stopped this overtaking of their homeland by fighting against the rees, but they also found out then that rees taste good. Since then, all neppers have been constantly hunting for and eating rees.
This odd phenomenon of one sentient species eating another is the only known one of its kind in the galaxy. However, it does entail that the predator doesn't always get the better of its prey. Rees are always looking for ways to outsmart neppers.
Helikase was an evil, evil nepper who began the longest-lasting war in galactic history. He founded the Nepzi Organization, which attempted to gain galactic domination by exterminating all other species.
Helikase was eventually killed, but there has been rumors of a shady organization attempting to summon his ghost. If this is done, it would begin another war without a doubt.
Neppers are one of only two species in the galaxy (the other being the Skaylians, which are almost exactly like humans) to wear clothes. All other species either wear suits (Foos, Rees) or don't wear anything at all (Fifis).