A Valerian transport that asks to dock at Deep Space 9 in 2369, becoming the pretext for a mutiny plot when Kira insists it is running weapons-grade dolamide to the Cardassians.
The Sherval Das appears in the first-season Deep Space Nine episode Dramatis Personae. The Valerians supplied dolamide to Cardassia during the occupation of Bajor, and Kira wants the ship turned away or searched, while Sisko, lacking proof, is unwilling to refuse it docking rights.
The disagreement is real, but it is blown out of proportion when a telepathic matrix left behind by the extinct Saltah'na takes hold of the senior staff and makes them re-enact the power struggle that destroyed that civilisation. Kira begins plotting to remove Sisko and seize the transport herself.
Odo, who is unaffected, eventually purges the influence from the crew. The question of the Sherval Das and its cargo is left behind by the larger crisis, and the ship is allowed to go on its way.