The Casciron were a humanoid species located in the Delta Quadrant. They were tall and imposing, with deep gray, glossy skin that was reminiscent of a shark. The way they showed greeting was to cross their arms over their chests, with the left wrist clasped beneath the right hand. The gesture was meant to show that the large, venomous stingers extending from their left wrists were being withheld from use. They believed that removing them would be an act of mutilation that offends the Allfather, a possible deity. By Casciron standards, being mutilated and experimented on was worse than being killed outright. At least one individual named Danros claimed that his species did not deceive, and even though they lost their world, they still had their pride.
In the year 2374 of an alternate timeline, the Casciron's world was destroyed by the Etanian Order. Following that, they began migrating into the Vostigye Union, where they were forced to have their venom glands removed. This led to some turning to piracy. B'Elanna Torres, saddened and frustrated over the death of Tom Paris, joined one of these pirate groups.
Under the formation of the Delta Coalition, there were plans to reverse the laws designating Casciron stingers as illicit lethal weapons. Also, Kes devised an inoculation that would protect Vostigye and other species from Casciron venom, as well as an experimental treatment to grow back removed stingers.
Plans were made to use both willing factions on the planet Kovoran as test subjects, with Kes bringing Neelix along as a well known diplomat to ensure cooperation on all sides. Unfortunately, B'Elanna's pirate group, believing harmful biological tests were being made on Casciron, destroyed the Kovoran research facility, nearly killing Neelix in the process. (ST - Myriad Universes novel: Places of Exile)