The black staves, or "black rods," are weapons created by the inhabitants of the ancient city of Kotl in the valley of Eodon. About the equivalent of a lit torch on other life forms in terms of damage, they are terrifyingly efficient against Myrmidex, which they were originally constructed to defeat. The end of the staff glows brightly to alert its wielder when Myrmidex are near (the staff need not be equipped to observe this effect). However, even these weapons couldn't save the ancient Kotl from their own creations in the end.
These are weapons, long, glossy-black rods with faint blue lights on the end. They can be used as war-staves -- just hit someone with one. But they're principally weapons against the Myrmidex, and you can attack Myrmidex at range with them, as though the black rods were guns. They discharge energy which is guaranteed to ruin a Myrmidex's whole day.